Find the Greatest Common Factor of the Monomials $16 x ^ { 10 }$

Find the greatest common factor of the monomials.
- $16 x ^ { 10 }$ and $20 x ^ { 6 }$

A) $4 x ^ { 6 }$
B) $20 x ^ { 4 }$
C) $16 x ^ { 6 }$
D) $4 \mathrm { x } ^ { 10 }$