Write the Complex Number in Standard Form $\sqrt { - 6 } \cdot \sqrt { - 7 }$

Multiple Choice

Write the complex number in standard form.​ $\sqrt { - 6 } \cdot \sqrt { - 7 }$ ​

A) ​- $\sqrt { 6 }$
B) $\sqrt { 7 }$
C) $\sqrt { 6 }$
D) - $\sqrt { 42 }$
E) $\sqrt { 42 }$