AKo in SB

[Rooger]

No hand history, so I take it from the memory.
My stack is around 100 BB, EP 50, MP 100, LP 60, BB 70.

I'm in the SB with A[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/club.gif[/img]
EP limps, MP raises to 4.5 BB, LP calls, action is on me.
Pot is currently 11.5 BB - I'm quite sure EP will call if I call, and fold if I reraise.

What is your action here? I see many different ways of playing this OOP.