Which equation is true for points on this curve?

A. $(x + 1)^2 + (y - 1)^2 = 1$
B. $x^2 + y^2 = 1$
C. $(x^2 + 1) + (y^2 - 1) = 1$
D. $(x + 1)^2 + (y - 1)^2 = 3$
E. $(x + 1)^2 + (y - 1)^2 = 9$