Ans: A
Note that $z=\dfrac{kx}{y^2}$, where $k$ is a non-zero constant. Then we have
Note that $z=\dfrac{kx}{y^2}$, where $k$ is a non-zero constant. Then we have
$\begin{array}{rcl}
z & = & \dfrac{kx}{y^2} \\
k & = & \dfrac{y^2z}{x} \\
\dfrac{1}{k} & = & \dfrac{x}{y^2z}
\end{array}$
