Correct option is B
Given: 1, 6, 30, (…) , 360, 720
The logic here involves multiplying the numbers by decreasing factors: 6, 5, 4, 3, 2.
1 × 6 = 6
6 × 5 = 30
30 × 4 =
120 (missing number)
120 × 3 = 360
360 × 2 = 720
Thus, the missing number is 120.
Hence, the correct answer is (b) 120.