Answer:
c. high levels of focus, attention, and concentration
Explanation:
Deliberate practice requires high levels of focus, attention, and concentration. This is based on the idea that individuals practice to harness their skills or to develop their ability in some specific field or domain. A musician will need to practice musical instruments with focus, attention to detail and with concentration if they want to improve and want to add further notes to their current level of performance. This applies to all sorts of practice and therefore option C is the answer.