Answer
An Ellipsoid as represented by $\bf{Graph(c)}$
Work Step by Step
Given: $9x^2+4y^2+2z^2=36$ ....(1)
Re-write as:
$\dfrac{9x^2}{36}+\dfrac{4y^2}{36}+\dfrac{2z^2}{36}=1$
or, $\dfrac{x^2}{(2)^2}+\dfrac{y^2}{(3)^2}+\dfrac{z^2}{(3 \sqrt 2)^2}=1$ ....(2)
Thus, the equation (2) shows a graph for an Ellipsoid as represented by $\bf{Graph(c)}$.
