The population reaches replacement level when the growth rate is:

The correct answer is Option (1) → zero

Option (1) zero — Correct. The growth rate of population is the difference between the birth rate and the death rate. When this difference is zero, or in practice very small, the population has ‘stabilised’ or reached the ‘replacement level’: just enough children are born to replace the older generations that are dying out.

Option (2) more than one — Incorrect. A growth rate above zero means births exceed deaths, so the population keeps growing; it has not stabilised.

Option (3) negative — Incorrect. A negative growth rate means fertility is below the replacement rate, so the population shrinks, as in Japan, Russia and Italy.

Option (4) positive — Incorrect. Any positive growth rate means more births than deaths; the population is still rising, however slowly, and new generations more than replace the old.