**Concept: The question tests on the area of Modern Math (Counting/Combinatorics)**

**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)**