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 directly as the square of $x$ , and $y = 2.4$ when $x = 4$ .

A) $y = 0.15 x ^ { 2 }$
B) $y = 1.72 x ^ { 2 }$
C) $y = 0.2 x ^ { 2 }$
D) $y = 0.19 \sqrt { x }$