A country currently has a high dependency ratio (ratio of children to adults). Which of the following scenarios could be true?

1. The country experienced a baby boom in the 1970s and birth rates have declined since then.
2. The country’s birth rates have been increasing dramatically over the past 20 years.
3. The government implemented pro-natalist policies about 10 years ago.
4. The country has maintained a modest natural increase rate for the past 30 years.

 I and III

 II and III

 I, II, and IV

 II, III, and IV

 All of the above