

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 HJ, and your holding is [King of Diamond and Nine of Diamond].
Before the flop, HJ raise 2.0 chips, and BB call. Assume that all other players that is not mentioned folded.
The flop comes Six Of Spade, Eight Of Diamond, and Seven Of Club, then BB check, and HJ check.
The turn comes Jack Of Spade, then BB bet 3 chips.
You currently have High Card(A-high).

Now it is your turn to make a move.
To remind you, the current pot size is 7.0 chips, and your holding is [King of Diamond and Nine of Diamond]. You currently have High Card.

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: