Write as a Real Number or a Product of a Real

Multiple Choice

Write as a real number or a product of a real number and i.
- $\frac { \sqrt { - 10 } \cdot \sqrt { - 5 } } { \sqrt { 2 } }$

A) 5
B) $25 \mathrm { i }$
C) $5 \mathrm { i }$
D) $- 5$