The significant population growth following World War II, was the baby boom. There is increase in the birth rate between 1946 and 1964, and the generation was born during that period.
Population was rapidly growth after the WWII as the medical facilities which was provided to the people after the fight was good now people.
Because of the WWII and Great Depression, people have postponed their marriages as the war ends up couples had babies. Young adults wanting to start families joined them in the nation's maternity wards.
Thus, option D is correct.
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