Provide an Appropriate Response $\mathrm { A }$ And $\mathrm { B }$

Multiple Choice

Provide an appropriate response.
-Suppose that $\mathrm { A }$ and $\mathrm { B }$ are both matrices of dimension $\mathrm { r } \times \mathrm { s }$ . Under what conditions can both the product $\mathrm { AB }$ and the product $\mathrm { BA }$ be found?

A) If $r = 1$
B) If $r = s$
C) If $r > 1$
D) There are no conditions under which both products can be found.