Students are sure to benefit from every minite---the best of

应该选C,意思是说,学生们一定能从分秒必争的学习中获益,
你可以进行部分改写：students make the best use of every minute to study...而题目中将主动改为了被动,只能在CD中选,
句子的主干是很简单的：Students are sure to benefit from every minite,学生们定能从没一分钟中获益,every minute后面的___the best of to study their lessons,其实是它的定语,用that 或which连接,所以选C.