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

A number is exactly divisible by $12$ if it satisfies the divisibility rules for both $3$ and $4$ ($12=3\times 4$, where $3$ and $4$ are co-prime numbers).
1. Divisibility Rule for 4: The last two digits of the number must be a multiple of $4$.

* Option A: $44$ is divisible by $4$.
* Option B: $56$ is divisible by $4$.
* Option C: $76$ is divisible by $4$.
* Option D: $28$ is divisible by $4$.
All options satisfy this criterion.

2. Divisibility Rule for 3: The sum of all individual digits must be divisible by $3$.

* Option A: $1+4+7+4+4=20$ (not divisible by $3$)
* Option B: $2+8+8+5+6=29$ (not divisible by $3$)
* Option C: $4+3+9+7+6=29$ (not divisible by $3$)
* Option D: $5+7+2+2+8=24$ (since $24$ is a multiple of $3$, this number is divisible by $3$)

Therefore, $57228$ is completely divisible by both $3$ and $4$, making it exactly divisible by $12$.