Perhaps the First Meaningful Evidence of Children's Attempts to Regulate

Perhaps the first meaningful evidence of children's attempts to regulate their emotions is

A) a 6-month-old's turning her body away from unpleasant stimuli
B) the attempts of 1-2-year-olds to control anger or sadness by compressing their lips
C) the ability of 3-year-olds to hide their guilt after telling a lie
D) the ability of 7-9-year-olds to mask their disappointment at receiving a gift they do not want