Write an Equation to Describe the Variation $R$ And Inversely as the Cube Of

Multiple Choice

Write an equation to describe the variation. Use k for the constant of proportionality.
-P varies directly as the square of $R$ and inversely as the cube of $S$ .

A) $\mathrm { P } = \frac { \mathrm { kS } ^ { 3 } } { \mathrm { R } ^ { 2 } }$
B) $P + R ^ { 2 } - S ^ { 3 } = k$
C) $P = \frac { k R ^ { 2 } } { s ^ { 3 } }$
D) $P R ^ { 2 } \mathrm {~S} ^ { 3 } = \mathrm { k }$