Pleaseee help!

Marie was trying to show her friend why -3 × -8 equals a positive product. This is what she wrote:

-3 × 0 = 0
-3 × (?) = 0
-3(8) + -3(-8) = 0


-24 + 24 = 0

What should Marie write in place of the question mark?
A. 8 + 8
B. -8 + (-8)
C. 8 + (-8)
D. -8 + 0