Siblings can be different from each other if they make the conscious effort to try to be different; this is known as the __________ effect.

A) calibration
B) conviction
C) comparison
D) contrast

The contrast effect refers to the phenomenon where people will perceive differences in stimuli based on comparison. In the case of siblings, if they consciously try to differentiate themselves from each other, this could create a contrast effect where their differences are emphasized and exaggerated.