Four-Year-Old Alonzo's Older Sister Kaylen Is in a High School

Four-year-old Alonzo's older sister Kaylen is in a high school play. Her character pretends to be a boy, so at one point she goes backstage and changes out of her elaborate dress into a peasant boy's clothes. After she does this, Alonzo asks his mother when Kaylen will come back on the stage. When mother points to Kaylen, Alonzo says, "He's a boy now!" Mother tries to explain that Kaylen's clothes have changed but she is still a girl, but Alonzo doesn't understand because he hasn't yet developed

A) preconventional reasoning.
B) postconventional reasoning.
C) gender constancy.
D) gender identity.
E) discriminative thinking.