Give a geometric description of the set of points in space whose coordinates satisfy the given pair of equations $y^2+z^2=36,x=y$ Choose the correct description. A The circle with center $(0,0,0)$ and radius $6$ in the plane $x=y$ B$.$ The ellipse formed by the intersection of the cylinder $y^2+z^2=36$ and the plane $x=y$ C$.$ The circle with center $(0,0,0)$ and radius $6$ in the $xy-$plane D$.$ The ellipse formed by the intersection of the eylinder $y^2+z^2=36$ and the $xy-$plane