If the birth rate in the same country later begins to fall as well, what will happen to the pace of natural increase?

Correct answer: It will generally slow

Natural increase is the difference between the birth rate and the death rate, without counting migration. If the birth rate later falls while the death rate does not rise correspondingly, the gap between births and deaths becomes smaller. The number added naturally to the population each year therefore decreases, so the pace of natural increase generally slows. Total population may still continue to grow for some time, but it grows more slowly rather than necessarily falling immediately.

Option B is correct. Option A is opposite to the expected effect of a declining birth rate. Option C is wrong because natural increase directly depends on the difference between births and deaths. Option D is unsupported: a fall in birth rate does not automatically cause death rate to rise. The word “generally” is important because the exact outcome depends on the levels and timing of both rates.