Find the Value of the Determinant $\left| \begin{array} { l l } - 10 & 5 \\0 & - 9\end{array} \right|$

Find the value of the determinant.
$\left| \begin{array} { l l } - 10 & 5 \\0 & - 9\end{array} \right|$

A) 90
B) -50
C) -90
D) 85