Erica points to the bus and calls it a car.What sort of error is this

A)  fast mapping
B)  overregularization 
C)  underextension
D)  overextension

Overextension

A linguistic error, common in early language development, in which a child applies a word in a broader context than is appropriate.

Underextension

A cognitive error observed in language development, where a child applies a word too narrowly, using it for one object instead of all objects of that category.

Fast Mapping

The process by which children are able to learn the meaning of new words quickly by making logical assumptions after a minimal exposure.