Rewrite the Expression Without Using Negative Exponents $3 x ^ { - 6 }$

Multiple Choice

Rewrite the expression without using negative exponents. (Assume all variables represent nonzero real numbers.)
- $3 x ^ { - 6 }$

A) $- 3 x$
B) $\frac { 3 } { x ^ { 6 } }$
C) $3 x ^ { 6 }$
D) $\frac { 1 } { 3 x ^ { 6 } }$