Three-Year-Old Hakeem's Parents Disagree Over Whether to Attend an Event

Three-year-old Hakeem's parents disagree over whether to attend an event related to his mother's job,and as they get more frustrated with each other,their voices grow louder.Unhappy and confused,Hakeem sticks his fingers in his ears.He is practicing

A) emotion regulation.
B) concrete operations.
C) conservation.
D) egocentrism.