Find the Determinant of the Given Matrix $$\left[ \begin{array} { r r r } 1 & 0 & 0 \\7 & - 3 & 0 \\- 3 & 7 & 7\end{array} \right]$$

Multiple Choice

Find the determinant of the given matrix.
- $$\left[ \begin{array} { r r r } 1 & 0 & 0 \\7 & - 3 & 0 \\- 3 & 7 & 7\end{array} \right]$$

A) 21
B) $- 28$
C) $- 21$
D) $- 70$