Saying That There Is a Sensitive Period for Human Language

Multiple Choice

Saying that there is a sensitive period for human language acquisition in early life means that

A) there is a time during development when children must be exposed to a language in order to master it.
B) children can become fluent in a language only if they are explicitly taught how to speak before the age of five.
C) it is impossible to learn to speak a second language fluently after age six.
D) children under the age of three are too young to begin learning a language.