Question

What is Net-Reproduction rate?
A. Number of deaths of children below one year of age per $1000$ live birth
B. Birth rate minus death rate
C. Average age to which a person at the time of his birth is expected to live
D. The rate at which women are replaced by daughters who will have children.

Answer 1

The net reproduction rate or ${R_o}$ in a population ecology and demography, is the average number of offspring that are more specifically daughters, who would be born to a female, if she passes through her lifetime conforming to age specific fertility and mortality rates of the given year. The net reproduction rate is similar to gross reproduction rate but in here, some of the females will die before completing their childbearing years is taken into account

Complete answer:
Option A Number of deaths of children below one year of age per $1000$ live birth: This is termed as infant mortality rate. It can be defined as the number of deaths per $1000$ live births of children, in which they are under one year of age. This is not a net reproduction rate.
Hence option A is not correct.
Option B Birth rate minus death rate: One can get the population index by subtracting death rate from the birth rate. Since this is not a net-reproduction rate.
So, option B is also not correct.
Option C Average age to which a person at the time of his birth is expected to live: A statistical measure of the average time which an organism is expected to live, based upon the year of their birth, their current age and other demographic factors which includes sex is termed as life expectancy.
Hence option C is also not correct, since this is not net-reproduction rate.
Option D The rate at which women are replaced by daughters who will have children: The average number of daughters born to a woman that will survive until childbearing ages, if they will experience the age-specific fertility and mortality rates of the current year, is termed as net-reproduction rate. The gross reproduction rate which is adjusted for female mortality can also be termed as net reproduction rate.
Hence option D is the correct answer.

Hence, Option D. The rate at which women are replaced by daughters who will have children is the correct answer.

Note:
The conditions under which generations are replaced can be measured using reproduction rate. This can be made taking account of mortality or the net reproduction rate; or without mortality or the gross reproduction rate. An ${R_0}$ of one generally means that each generation of mother is having exactly enough daughters which can replace themselves in the population.