13. Peter, Emma, and Keller play chess. Peter won 4 games and lost 2 games; Emma won 3 games and lost 3 games. If Keller lost 3 games, then he won ( ) games.
(A) 0
(B) 1
(C) 2
(D) 3
(E) 4
13. B.

It is clear that in each game, one side must win and the other must lose.
Therefore, from the total number of games played being equal to the total number of losses, we have
$$
(2+3+3)-(4+3)=1 \text{, }
$$

which means Keller won one game.