Which social reason can contribute to maintaining a high birth rate?

Correct answer: Low age at marriage and social acceptance of large families.

The correct answer is A. Birth rate is the number of live births in relation to the population during a specified period. Social customs can influence when people marry and how many children families consider desirable. If marriage occurs at a relatively young age and large families are socially accepted, the period during which births may occur can be longer, and families may prefer more children. These conditions can help maintain a high birth rate, although economic, health and educational factors also matter. A is correct because it identifies two social influences connected with fertility. B is wrong because an old population generally contains fewer people in the main childbearing ages, so it does not by itself maintain a high birth rate. C is wrong because everyone leaving would reduce the local population, not directly create births. D is wrong because complete urban services do not necessarily produce a high birth rate and often accompany changing family preferences. Memory cue: social customs can shape fertility decisions.