Write $\sqrt { 5 } \sqrt { - 49 }$ In Terms of I , Perform the Indicated Operations, and In Terms

Write $\sqrt { 5 } \sqrt { - 49 }$ in terms of i , perform the indicated operations, and simplify.

A) $7 i \sqrt { 5 }$
B) $7 \sqrt { 5 }$
C) $- 7 i \sqrt { 5 }$
D) $7 \sqrt { 5 i }$
E) $- 7 \sqrt { 5 }$