Multiply and Then, If Possible, Simplify by Factoring $\sqrt{64} \sqrt{4}$ A) $4 \sqrt{16}$

Multiply and then, if possible, simplify by factoring.
- $\sqrt{64} \sqrt{4}$

A) $4 \sqrt{16}$
B) $4 \sqrt{4}$
C) 256
D) 16