Which of the numbers given below is exactly divisible by 12?

A number to be exactly divisible by 12, it should be divisible by 4 and 3 

To check whether a number is divisible by 3, the sum of all the digits of a number should be divisible by 3 and
To check whether a number is divisible by 4, the last 2 numbers should be divisible by 4

For, 43688 sum of all the digits = 4+3+6+8+8 = 29(which is not divisible by 3)
For, 14632 sum of all the digits = 1+4+6+3+2 = 16(which is not divisible by 3)
For, 28544 sum of all the digits = 2+8+5+4+4 = 23(which is not divisible by 3)
For, 57816 sum of all the digits = 5+7+8+1+6 = 27(divisible by 3)
And also the last 2 numbers (16) are divisible by 4. So, 57816 is divisible by 12

Hence, option D is the correct answer.