Fill in the Blank with One of the Words or Phrases

Multiple Choice

Fill in the blank with one of the words or phrases listed below. $$\begin{array} { l l l } \text { circle } & \text { ellipse } & \text { hyperbola } \\\text { conic sections } & \text { vertex } & \text { diameter } \\\text { center } & \text { radius } & \text { nonlinear system of equations }\end{array}$$
-The circle, parabola, ellipse, and hyperbola are called the .

A) conic sections
B) center
C) nonlinear system of equations
D) vertex