After a long and trying day filled with tantrums and arguments from his toddler, a young father threw up his hands in despair and said, "Now I know what they mean by the terrible twos!" The most probable reason for this phenomenon is that ______

a. parents get worn out by the time they have spent two years with their children
b. the child is insecure
c. the child is making the transition from the preoperational to the concrete
operational stage
d. it is often difficult for children of this age to find a balance between dependence
and autonomy

d