Preflop: KK on the button

[ajmargarine]

Perplexed was I.

Party Poker No-Limit Hold'em, $ BB (6 handed) internettexasholdem.com

Hero ($101.95)
SB ($82.30)
BB ($39.15)
UTG ($226.77)
MP ($94.40)
CO ($119.05)

Preflop: Hero is Button with K[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/club.gif[/img]. SB posts a blind of $0.50.
<font color="#CC3333">UTG raises to $2</font>, <font color="#CC3333">MP raises to $7</font>, CO calls $7, Hero...

UTG is a donkey, I don't care too much about him here.
MP is a tight TAG, 19/10; seems decent.
CO is a nit, 6/3; only 45 hands tho.

Hero's action?