Concept: The question tests on the basics of Counting
Solution
4 consonants can be chosen out of 7 in 7C4 = 7C3 = (7 * 6 * 5) / (3 * 2 * 1) = 35 ways
2 vowels can be chosen out of 4 in 4C2 = (4 * 3) / ( 2 * 1) = 6 ways
These chosen letters can be arranged in 6! = 720 ways
Total number of ways = 35 * 6 * 720 = 151200 ways
Option C