Describe the Level Curves of the Function $f ( x , y ) = \sqrt { x ^ { 2 } + ( y - 1 ) ^ { 2 } } - y$

Multiple Choice

Describe the level curves of the function $f ( x , y ) = \sqrt { x ^ { 2 } + ( y - 1 ) ^ { 2 } } - y$ .

A) Concentric circles
B) Non-concentric circles
C) Concentric ellipses (not circles)
D) Non-concentric ellipses (not circles)
E) Parabolas with the same vertex
F) Parabolas with the same focus
G) Hyperbolas with the same vertices
H) Hyperbolas with the same foci