When a child starts using overregularizations,what do these errors reflect

A)  The child is learning to apply rules to language. 
B)  The child will soon start using telegraphic speech. 
C)  The child is fast mapping. 
D)  The child has slightly delayed development.

Overregularizations reflect a child's developing knowledge of grammar rules and their attempts to apply those rules consistently, even when they do not fit the particular context. It is a normal stage of language development, and not necessarily a sign of delayed development.