What should be Total Fertility Rate (TFR) of a population in order to reach at the replacement level of fertility?

1. A

   1.0

   A TFR of 1.0 is far below replacement; it would shrink a closed population rapidly.

2. B

   1.6

   1.6 is typical of several low-fertility countries, still below replacement in the Indian textbook sense.

3. C

   2.1

   Replacement-level fertility is taken as a TFR of about 2.1 in India (two children plus a margin for mortality and the sex ratio at birth). That is the official key.

4. D

   2.3

   2.3 is above replacement; it was closer to older national averages, not the replacement benchmark.

Summary. Official key is (c) 2.1. Replacement TFR is the rate at which a generation just replaces itself. NFHS and Census commentary use 2.1 as the Indian threshold. Honour the stored letter (c).