While being dressed for bed, 7-month-old Darnell picked up new baby's comb that his mother just bought for him. Darnell had never seen this before and didn't know how it was used, so he tried to put it in his mouth. Piaget might say that Darnell was .a) assimilating the comb into his existing schemes.
b) accommodating the comb into his existing schemes.
c) adapting the comb into his exiting schemes.
d) adapting the comb with Substage 3: Secondary circular reactions.