Write the Expression with Only Positive Exponents $\mathrm{r}^{-3}$ A) $\mathrm{r}^{1 / 3}$

Multiple Choice

Write the expression with only positive exponents. Assume all variables represent nonzero numbers. Simplify if necessary.
- $\mathrm{r}^{-3}$

A) $\mathrm{r}^{1 / 3}$

B) $\frac{1}{r^{3}}$

C) $-\frac{1}{r^{3}}$

D) $-r^{3}$