

You are a specialist in playing 6-handed No Limit Texas Holdem. The following will be a game scenario and you need to make the optimal decision.

Here is a game summary:

The small blind is 0.5 chips and the big blind is 1 chips. Everyone started with 100 chips.
The player positions involved in this game are UTG, HJ, CO, BTN, SB, BB.
In this hand, your position is CO, and your holding is [King of Spade and Jack of Diamond].
Before the flop, CO raise 2.3 chips, and BB call. Assume that all other players that is not mentioned folded.
The flop comes Nine Of Diamond, Ten Of Spade, and Eight Of Spade, then BB check, CO bet 2 chips, and BB call.
The turn comes Five Of Diamond, then BB check, and CO check.
The river comes Two Of Diamond, then BB check.


Now it is your turn to make a move.
To remind you, the current pot size is 9.0 chips, and your holding is [King of Spade and Jack of Diamond].

Decide on an action based on the strength of your hand on this board, your position, and actions before you. Do not explain your answer.
Your optimal action is: