Baby Billy calls his favorite blanket a "blankie." When he sees other blankets in the house, however, he does not refer to them as "blankie" because he uses that name only for his favorite blanket. This is an example of .

Underextension

Explanation:

Underextension can be described as term which is used improperly for one object instead of all the objects of that kind. This action often occurs in children when they are initially acquiring and developing language.Baby Billie also uses underextension to call his favorite blanket as blankie and calls all the other blankets correctly.

the answer is d. amendments.

you answered your own : -/