All the Following Are Examples of Critical-Period Effects EXCEPT

All the following are examples of critical-period effects EXCEPT:

A) adults pick up vocabulary in a second language more quickly than do children due to their fast mapping skills
B) adults learning a second language may speak with an accent, whereas children learning a second language may sound like a native
C) those who learned English later in life show poorer grammatical abilities than those who learned English before their fifth birthday
D) children who grow up without human communication struggle to learn the grammatical structure of any first language at a later age