The word "precept" ( Line 4, Para. 3) probably means " ______. ".

A．parents should be strict with their children
B．parental controls reflect only the needs of the parents and the values of the community
C．parental restrictions vary, and are not always enforced for the benefit of the children alone
D．parents vary in their strictness towards their children according to the situation

A．should encourage them to read before they know the meaning of the words they read
B．should not expect too much of them
C．should achieve a balance between pushing them too hard and leaving them on their own
D．should create as many learning opportunities as possible