The Sizes of Two Matrices a and B Are Given $A$

The sizes of two matrices A and B are given. Find the sizes of the product AB and the product BA, if the products are
defined.
- $A$ is $2 \times 4$ , B is $2 \times 4$ .

A) $\mathrm { AB }$ is $2 \times 4 , \mathrm { BA }$ is $4 \times 2$ .
B) $\mathrm { AB }$ is $2 \times 2 , \mathrm { BA }$ is $4 \times 4$ .
C) $A B$ is undefined, $B A$ is undefined.
D) $\mathrm { AB }$ is $4 \times 2$ , $\mathrm { BA }$ is $2 \times 4$ .