Fourteen-Month-Old Adrian Can Say "Bye-Bye," "Mama," "Da-Da," and "Doggie

Fourteen-month-old Adrian can say "bye-bye," "mama," "da-da," and "doggie." You can safely conclude that Adrian:

A) cannot distinguish between friendly and angry talking.
B) cannot respond to a simple command, such as "Give mama the ball."
C) understands many more words than he can speak.
D) will enter the two-word stage within the next month.