Answer:
64 rabbits!
Explanation:
In a year there are 12 months. This can be divided into three divisions of four months each.
Initially it is given there were 8 rabbits. This means at the end of first four months it would have doubled. That is there should have been 16 rabbit at the end of first four months.
In the next four months this doubles again to give us 32 rabbits.
And at the last four months these 32 rabbits double to give 64 rabbits.
[This can also be viewed as a Geometric progression with first term, a = 8 and the common difference, r = 2.]