The two groups of rabbits grow exponentially and linearly respectively.
For group M with an exponential growth model where the population doubles each year, we have the model to be:

For group N with a linear model, we have the model to be:

where m is the rate of change of the population of rabbits.
After 3 years, both populations are equal. Hence, we can put t = 3 into the equations and equate them to one another:

Solving for m, we have:

OPTION D is correct.