The mathematics scores of some of the students are given below. ( out of 30)

12, 14, 16, 15, 20, 23, 26, 28, 29, 22, 30
Teacher wanted to find the representative value of their scores such that she could say that half of students have scored marks above that and half of the students have scored marks below that? What was that score?

a) 20 b) 22 c) 21 d) 23