Simplify the Expression $( - 5 + \sqrt { - 15 } ) ( 1 - \sqrt { - 15 } )$

Multiple Choice

Simplify the expression. Enter the answer in a + bi form. $( - 5 + \sqrt { - 15 } ) ( 1 - \sqrt { - 15 } )$

A) $10 - 6 \sqrt { 15 i }$
B) $10 + 6 \sqrt { 15 i }$
C) $- 20 + 6 \sqrt { 15 i }$
D) $- 20 - 6 \sqrt { 15 } i$