If $A$ Is A $3 \times 4$ Matrix and the Matrix Sum $A+B$

Multiple Choice

If $A$ is a $3 \times 4$ matrix and the matrix sum $A+B$ exists, what can you say about the matrix $B$ ?

A) B is a matrix with 3 rows
B) B is a $3 \times 4$ matrix
C) B is a matrix with 4 rows
D) B is a matrix with 4 columns