Thirteen-Month-Old Olaf Has Begun to Raise the Pitch of His

Multiple Choice

Thirteen-month-old Olaf has begun to raise the pitch of his voice at the end of a babble. If Olaf is being raised by English-speaking parents, his behavior may reflect the precursor of his ability to

A) ask a question.
B) produce infant-directed speech.
C) make a declarative statement.
D) coo.