Find the equation in standard form for the circle whose diameter has an endpoint at (-3, -4) and the origin.

a...4 x 2 + 4 y 2 - 12 x + 16 y = 0
b...4 x 2 + 4 y 2 + 12 x - 16 y = 0
c...4 x 2 + 4 y 2 - 12 x - 16 y = 0
d...4 x 2 + 4 y 2 + 12 x + 16 y = 0