Researchers Manipulated Exposure to Body Images by Randomly Assigning Young

Researchers manipulated exposure to body images by randomly assigning young girls to one of three conditions.They observed that young girls' body dissatisfaction was greatest after viewing very thin images of a Barbie doll compared to normal-weight images ("Emme" doll) or neutral images.The alternative explanation that girls in the Barbie condition might have weighed more prior to exposure to body images can be ruled out because the researchers

A) held constant the amount of time girls looked at images.
B) manipulated the type of exposure with three conditions.
C) randomly assigned girls to the different exposure conditions.
D) all of these