Which evidence best supports the claim that living in a foreign country is the smartest way to learn a new language?

a: i really hope to spend a semester in paris because it is the perfect place to see cultural landmarks and improve my french.
b: a television advertisement encourages students to purchase language study software and guarantees a forty-five percent improvement in six weeks.
c: my father spent several years in peru and learned to speak spanish so fluently that people thought he was a native peruvian.
d: language researchers found that students who lived in a foreign country learned the new language sixty-five percent faster than students learning at home.

read the counterclaim in an argumentative essay about the benefits of participating in marching band.

some people claim that the only benefit of marching band is learning to play an instrument.

which rebuttal best addresses the counterclaim?

a: however, learning to play an instrument is not necessarily important for every student.
b: however, learning to play an instrument has been proven to improve grades and test performance.
c: however, most marching band members also get a great amount of exercise and establish lifelong friendships.
d: however, most marching band members learn to play only one instrument during their band years.