Although Most Children Are at Least Somewhat Aware of When

Although most children are at least somewhat aware of when they are exhibiting selfish behavior, most children also fail to stop this behavior without prompting. This is because the benefits of selfish behavior, such as refusing to share a toy, are immediately apparent, whereas the benefits from generosity are harder to see and much harder for a child to comprehend. Therefore, if we want children to be more generous, it is necessary to _____________________________.
Which of the following would most logically complete the passage?

A) Allow them to discover the benefits of generosity on their own.
B) Practice generosity in our own lives since children will fail to do the same.
C) Allow children to exhibit selfish behavior in at least small quantities.
D) Explain to children the value of generosity and its benefits so they will begin to understand.
E) Punish children when they refuse to share a toy.