If a country's population pyramid shows a base that is dramatically narrower than the middle sections, what does this suggest?

Question

Accepted Answer

There was a significant event like war or disaster that eliminated an entire generation previously.. A narrow base relative to older cohorts suggests a sharp reduction in birth rates, possibly following a catastrophic event that impacted younger demographics (though war impacting mid-20s/30s more directly). Given the options, this best reflects a sudden demographic shock affecting births.