Find an Equation of Variation in Which the Following Are $y$

Multiple Choice

Find an equation of variation in which the following are true.
- $y$ varies jointly as $x$ and $p$ and inversely as the square of $s$ , and $y = \frac { 9 } { 2 }$ when $x = 1 , p = 9$ , and $s = 4$ .

A) $y = \frac { 12x p ^ { 2 } } { s }$
B) $y = \frac { 32 x ^ { 2 } p } { s ^ { 2 } }$
C) $y = \frac { 8 x p } { s ^ { 2 } }$
D) $\mathrm { y } = 9 \mathrm { xps } ^ { 2 }$