Answer:
B. However, learning to play an instrument has been proven to improve grades and test performance.
Step-by-step explanation:
A counterclaim is a claim used to rebut a previous claim. The counterclaim shown in this example is that some people claim that the only benefit of a marching band is learning to play an instrument.
Our task is to determine which claim most successfully rebuts this one. The best option is option B. Our claim needs to contain evidence that participants of marching bands can benefit from them even more than learning to play an instrument. According to this option, the participants get better grades and perform better on tests. The important aspect of this statement is that this has been scientifically proven, which makes it reliable.
The second best option is option C, because it also contains the benefits of marching bands. However, it doesn't contain any scientific evidence.
Options A and D don't contain any benefits, which makes them incorrect.