A selection is to be made for one post of principal and two posts of vice-principal amongst the six candidates called for the interview only two are eligible for the post of principal while they all are eligible for the post of vice-principal. The number of possible combinations of selectees is___________?

A. 4
B. 12
C. 18
D. None of these

Explanation:

Total number of ways = 2C1 . 5C2 = 2 x 5!/3!2! = 2 x 10 = 210