Which of the Following Strategies Is Beneficial for Parents to Use

Which of the following strategies is beneficial for parents to use to get their child to practice the violin?

A) Reward him with extrinsic rewards only after he reaches a level of competence.
B) Ignore his efforts to practice so he won't know how important it is.
C) Reward his practice efforts even when done poorly or without enthusiasm.
D) Encourage him to focus on how playing the violin is personally rewarding.