Many babies were born after the end of the World War II but the recorded year where most baby boomer were born was in 1957. 4.3 million baby boomers that was born was recorded on that year. After 1957, the birth rate slowly declined.
You should give more details, though.
If you mean to Brainly, I think that more options should be added for more students to join.
I'd say its A, because after wars things start to decline.
I hope this is right and helped you out.