By choosing different values of a in the system of equations
x^2 - y^2 = 0
(x-a)^2 + y^2 = 1 It is possible for the number of distinct solutions to be:
A) 0,1,2,3,4 or 5
B) 0,1,2 or 4
C) 0,2,3 or 4
D) 0,2 or 4
E) 2 or 4
The following graph should help:
