Answer: Option C
Number of ways of selecting (3 consonants out of 7) and (2 vowels out of 4)
$$\eqalign{
& = \left( {{}^7{C_3} \times {}^4{C_2}} \right) \cr
& = \left( {\frac{{7 \times 6 \times 5}}{{3 \times 2 \times 1}} \times \frac{{4 \times 3}}{{2 \times 1}}} \right) \cr
& = 210 \cr} $$
Number of groups, each having 3 consonants and 2 vowels = 210
Each group contains 5 letters.
Number of ways of arranging 5 letters among themselves
= 5!
= 5 x 4 x 3 x 2 x 1
= 120
∴ Required number of ways = (210 x 120) = 25200