The decision to join the social sector is often not the first choice between (A) / among (B) students.
Increasingly a (A) /the (B) number of students are also getting lured to the sector by prestigious fellowships, such as the Gandhi Fellowship that was started in 2008.
Marketing, which never seemed to be my cup of tea,(A) / coffee (B) was now my field of interest.
“Between” is used for two persons and “Among” for more than two persons. “A number of” is plural but “the number of” is singular. “one's cup of tea” means “of one's choice or preference”. “one's cup of coffee”is a meaningless expression.