Which one of the following instances is an example of qualitative change?
A. Last year two-year-old Helga could not talk, but now she can carry on a conversation.
B. Fifteen-year-old Marty grew 3 inches over the summer. He is now taller than Dad.
C. Nine-year-old Billy Bob can jump 2 inches higher now than he could last month.
D. Topia has learned 2 new words.
I am a little confused, but my choice is A. Is that right?