Find the missing letter in the series: M, N, O, P, ?

A. Q

If the word 'SCHOOL' is coded as 'VFRRSP', what is the code for 'TEACH'?

A. WHDFK

What is the next letter in the series: A, E, I, M, ?

A. O

Happy: Sad: Joyful

D. CHEERFUL

In a sequence of letters: M, O, Q, S, ?, Y. What is the missing letter?

A. T