State the type of the quadratic surface:
$x^2 + \left( \frac{y}{3} \right)^2 + z^2=1$

1. Hyperboloid of two sheets
2. Hyperboloid of one sheet
3. Ellipsoid
4. None of these

Describe the trace obtained by intersecting with the plane $y=0$:

1. Ellipse
2. Hyperbola
3. Circle
4. Empty set