It is known that $\triangle A B C$ is an equilateral triangle with area $\frac { 9 \sqrt { 3 } } { 4 }$ , and all its vertices lie on the surface of sphere $O$. If the surface area of sphere $O$ is $16 \pi$ , then the distance from $O$ to plane $A B C$ is
A．$\sqrt { 3 }$
B．$\frac { 3 } { 2 }$
C． 1
D．$\frac { \sqrt { 3 } } { 2 }$