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.