The correct option is C 6
For the number to be divisible by 6, it must be divisible by both 2 and 3.
Hence, d must be an even number.
Also, the sum of the digits, 7+4+1+d=12+d must be divisible by 3.
12 is divisible by 3.
∴d can be 0 or any even number that is also a multiple of 3, i.e., 6.
3×1=3
3×2=6
3×3=9
∴d can be 0 or 6.
Such numbers are 7410 and 7416.