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
a4a3
d4b4
d4c4
d4d1
d4d2
d4d3
d4f4
d4e4
d4d8
d4d7
d4d6
d4d5
e5e4
f5f4
h5h4
c7d8
c7d7
c7c8
c7b8
c7b7

## Board State Fen
8/2k5/5R2/4pp1p/p2r2p1/2K3P1/P4P1P/8 b - - 9 77
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
a4a3
d4b4
d4c4
d4d1
d4d2
d4d3
d4f4
d4e4
d4d8
d4d7
d4d6
d4d5
e5e4
f5f4
h5h4
c7d8
c7d7
c7c8
c7b8
c7b7

## Board State Fen
8/2k5/5R2/4pp1p/p2r2p1/2K3P1/P4P1P/8 b - - 9 77
assistant
f5f4