The author considers that a fairy story is more effective when it is ______.

A．he is born with the capacity to speak
B．he has a brain more complex than an animal's
C．he can produce his own sentences
D．he owes his speech ability to good nursing

A．to prove that children are bom with the ability to speak
B．to discover what language a child would speak without hearing any human speech
C．to find out what role careful nursing would play in teaching a child to speak
D．to prove that a child would be damaged without learning a language