The reconstructed board:
LYGUJ SLEDW MANBI VFTHC EROPK
The following matrix gives the fewest moves to get to any square given robots starting on A, B, and C:
2 1 2 1 1 4 5 5 4 3 1 0 1 0 1 1 5 5 4 0 2 1 2 1 1
The highest number is 5, which occurs for squares occupied by the letters L,E,F,T. Thus the answer is LEFT.