It was "B. Philippe de Vitry" who was a Medieval composer and was also a politician and author famous for his writings on music theory, since at the time not many people knew the fundamentals of such theory.
2. Colonists could only trade with England
"B. The capitalist<span> system encourages competition among businesses"</span> is correct. Capitalism, although it definitely has flaws, encourages competition because in theory the person or company with the best idea makes the most money.
Ethnicity is like your culture. Language, race, and religion all play into your background and culture. However, politics are something that govern the country you live in -- they're not necessarily connected to your background. Therefore, politics would be the correct answer.