Find the Determinant of the Matrix Below $\left[ \begin{array} { c c } 5 & - 5 \\1 & 1\end{array} \right]$

Multiple Choice

Find the determinant of the matrix below. $\left[ \begin{array} { c c } 5 & - 5 \\1 & 1\end{array} \right]$

A) 25
B) 10
C) -20
D) -10
E) -25