Who will be Wenger’s defensive saviour: Spahic, Cahill, Mertsacker, Upson or Subotic?

Arsene Wenger has fully recognised his central defensive woes and admitted now Sebastien Squillachi and Thomas Vermaelen have been ruled out with injury that he may have to look at bringing in some support.
Rumours are rife about who could step in and with Chelsea also chasing some defenisive support, no signings will be easy. So here we have taken a look at the top targets and tried to work out who would be best for the Gunners.
Gary Cahill
Nationality: English
Age:25
Current team: Bolton Wanderers
Height: 6.0ft
For current club: 95 League appearances with 8 goals
Value: £15-18million with £20million price tag
Other clubs interested: Chelsea
Gary Cahill's solid skills at the back for Bolton have earned him wide acclaim, with rival interest from Chelsea. Bolton manager Owen Coyle is unwilling to sell the player and has slapped a £20million price tag on him, but their interest in Middlesbrough player David Wheater may mean they are considering Cahill's sale. He would strengthen the often liable Arsenal defense and would not be cup-tied in Europe.
Phil Jagielka
Nationality: English (Polish)
Age: 28
Current Team: Everton
Height: 6.0ft
For current club: 90 League starts with 1 goal
Value: £10-12million
Other clubs interested:
Jagielka has crossed the lips of Arsene Wenger many a time as the French man rates the Everton player highly, but so does his manger David Moyes. The versatile defender can also play in midfield and has even played in goal before. With Jagielka's current injury he would be a doubt for movement as his own club do not have defenders of his quality falling out their ears.
Per Mertesacker
Nationality: German
Age: 26
Current Team: Werder Bremen
Height: 6.6ft
For current club: 126 League games with 10 goals
Value: £10-12million
Other clubs interested: Liverpool
The Werder Bremen big man has been on the Arsenal radar for some time now, especially after the German international put in some quality performances during their rampant World Cup campaign. Though Mertesacker has done his best to avoid speculation, with his club in the bottom half of the Bundesliga he said: 'We are in a difficult moment with Werder and we should not be talking about me at this time.'
Matthew Upson
Nationality: English
Age: 31
Curent Team: West Ham
Height:6.0ft
For current club: 122 league appearances with 4 goals.
Value: £3.5-6million, market value £7million
Other clubs interested:
One of two old boys that Wenger has supposedly considered is West Ham player Matthew Upson. He played for Arsenal between '97-'03 before being sold to Birmingham for £10million. He might be valued reasonably low but Wenger has admitted he would like a player with Premier League experience and with West Ham's top flight football future looking a little hazy he might want to pack his bags and head across to north London, even as a fringe player.
Sol Campbell
Nationality: English
Age: 36
Current Team: Newcastle United
Height: 6.2ft
For current club: 3 League starts for Newcastle,
Value: loan or £1.5million
Other clubs interested:
The second of the old boys is Sol Campbell. A man that knows his way around North London and around the Arsenal set-up in general. If Sol did return it would be his third period in an Arsenal shirt after providing support at the end of the '09/'10 season. Unhappy with warming the bench at Newcastle and probably missing the bustle of Finsbury Park it would probably be a dream move for Campbell.
Neven Subotic
Nationality: Serbian (US)
Age: 22
Current Team: Borussia Dortmund
Height: 6.4ft
For current club: 84 League appearances with 6 goals
Value: £15-20million
Other clubs interested: Manchester United, Chelsea, Manchester City, Real Madrid and Liverpool
He has become the talk of the transfer window, the young Serb has proved himself to world football after playing every minute of Borussia Dortmund's Bundesliga outings last season. His breakthrough to the Serbian national team this summer was significant as they have Nemanja Vidic and Aleksander Lukovic to choose from. He is a young talent, with a hefty price tag that may put the thrifty Wenger off.
Emir Spahic
Nationality: Bosnian
Age: 30
Current Team: Montpellier
Height: 6.0ft
For current club: 50 starts and 2 goals
Value: £4-10million
Other clubs interested:
The Montepellier player has been chased by Wenger since last season, but the deal fell-through. He is a bit of an unknown, yet this would suit Wenger's usual buying style and with experince in the French Ligue 1 his style should fit in well with team-mates. He is keen for a move to the Emirates saying:“If Arsenal were interested again I could not say no."