Using Matrix $A=\left[\begin{array}{rrr}3 & 7 & 4 \\2 & -1 & 6\end{array}\right]$

Multiple Choice

Using matrix $A=\left[\begin{array}{rrr}3 & 7 & 4 \\2 & -1 & 6\end{array}\right]$ and $B=\left[\begin{array}{rrr}-1 & 5 & 2 \\7 & 10 & 1 \\-2 & 5 & -1\end{array}\right]$ which of the following is a true statement?

A) Matrix A has an inverse.
B) $A+B=\left[\begin{array}{rrr}2 & 12 & 6 \\9 & 9 & 7 \\-2 & 5 & -1\end{array}\right]$
C) AB exists and BA does not exist.
D) BA exists and AB does not exist.