As Children Move Beyond the Telegraphic Period into More Sophisticated

Multiple Choice

As children move beyond the telegraphic period into more sophisticated use of grammar, morphemes such as -ing and -s are acquired before morphemes such as -ed and -'s.What does Brown attribute this order to?

A) The morphemes -ing and -s are used more frequently by adults.
B) The morphemes -ing and -s are less semantically complex.
C) The morphemes -ing and -s are phonetically easier to pronounce.
D) The morphemes -ing and -s are both verb transformations, which are typically mastered prior to noun transformations.