Answer
Elliptical cone (graph h).
Work Step by Step
Since, we have $x^2+4z^2=y^2$
This can be re-written as:
$\dfrac{x^2}{1}+\dfrac{z^2}{(1/2)^2}=\dfrac{y^2}{1}$
Since, the equation is a graph for an Elliptical cone along the y-axis as shown in graph (h).
