Find the Value of a If the Following Matrix Is $\left[ \begin{array} { l l } - 4 & 2 \\- 6 & a\end{array} \right]$

Multiple Choice

Find the value of a if the following matrix is singular $\left[ \begin{array} { l l } - 4 & 2 \\- 6 & a\end{array} \right]$

A) $\frac { 1 } { 3 }$
B) 3
C) 0
D) $- \frac { 1 } { 3 }$
E) $- 3$