Suppose population a is small and the species has a short generation time, while population b is large and has a long generation time. which will be faster to adapt? which will be more resilient in the face of environmental change?

For the answer to the question above, I believe the answer to the question above is the
Population b is large and has a long generation time.
Because of their generation time, they could adapt and thrive more in the changing environment rather than the generation with short time.