Given the available moves based on the current board state in FEN notation, think carefully about which move would be best, then make that move. Be sure to note your color indicated in the FEN notation before deciding.
## Available Moves
a1b1
c1a3
c1b2
c1h6
c1g5
c1f4
c1e3
c1d2
e1d1
e1f1
e1e3
e1e2
g1h1
g1f2
g1f1
a2a4
a2a3
g2f1
g2h1
g2h3
h2h4
h2h3
f3f4
g3g4
c4c5

## Board State Fen
6k1/1r3pp1/2p4p/p3p3/2PrP3/5PP1/P1b3BP/RnB1R1K1 w - - 1 39
system
You are a chess playing AI.
user
Given the available moves based on the current board state in FEN notation, think carefully about which move would be best, then make that move. Be sure to note your color indicated in the FEN notation before deciding.
## Available Moves
a1b1
c1a3
c1b2
c1h6
c1g5
c1f4
c1e3
c1d2
e1d1
e1f1
e1e3
e1e2
g1h1
g1f2
g1f1
a2a4
a2a3
g2f1
g2h1
g2h3
h2h4
h2h3
f3f4
g3g4
c4c5

## Board State Fen
6k1/1r3pp1/2p4p/p3p3/2PrP3/5PP1/P1b3BP/RnB1R1K1 w - - 1 39
assistant
c4c5