Answer:
Based on the clues, the word that would best replace "determine" is:
C. driven.
Explanation:
Depending on the context, any of the options provided could be a synonym for "determined". But, once we analyze the context and the clues of this particular passage, we can see why "driven" is the best choice. The speaker is describing his/her brother as someone who is deeply motivated. He practices hard and has a clear goal in mind. This is not about how strong-headed or how inflexible he is when others try to convince him to do something else. It is all about determination, motivation, drive.
