What objects are used for each conic

I need some help with algebra two homework on conics. Here is the question:

In the coordinate plane, each conic is defined by distances from given objects. What objects are used for each conic? Choose from: two points, a single point, or a point and a line.

a. a circle

b. an allipse

c. a hyperbola

d. a parabola

Thanks for any help.. ((:

circle: single point

ellipse: two points

hyperbola: two points

parabola: a point and a line