What Is a Proposed Reason for Why Students with Autism

What is a proposed reason for why students with autism often have trouble with verb tenses and articles, even if they have syntactic awareness and are able to use the common grammatical morphemes?

A) The students can memorize what words mean but may fail to use that vocabulary for a variety of functions
B) The students are not able to duplicate appropriate intonation, pitch, and articulation patterns
C) Referents change according to the speaker's point of view
D) Lack of mastery of pragmatics