The correct option is A high birth rates
A large proportion of children in a population is a result of high birth rates. The birth rate is the total number of live births per 1000 of a population in a year. The birth rate are used to calculate population growth . There are many causes of high birth rate in India for eg; Early and Universal Marriage, preference for male child, joint family system, climatic factor, poverty, high infant mortality, inadequate supply of family welfare services, inadequate recreational facilities, effect of religion and agricultural occupation etc.