How many meaningful words can be formed using fourth, eighth, tenth and twelfth letters of the word “PREPARATIONS”, using each letter only once in each word?

​Given:​

P R E P A R A T I O N S
1 2 3 4 5 6 7 8 9 10 11 12

Required letters:
4th = P
8th = T
10th = O
12th = S

So, letters are P, T, O, S

Meaningful words formed using all four letters once are:
STOP
TOPS
POST
SPOT
POTS

Total meaningful words = 5

Thus, correct option is (C) Five.