Which of the following is a likely cause of the shape of the population graph of Mexico?

Question

(1) Mexico has adopted China's "one family-one child" program.
(2) About 60 percent of Mexico's industrial workers live in or near Mexico City.
(3) Much of the land in northern Mexico is too dry for farming.
(4) Medical and health limitations may have affected life expectancy in Mexico.
(5) Unemployment has resulted in an inadequate tax base in Mexico.
I believe the answer is 5 is this correct ?

Answer 1

What does a tax base have to do with the population graph?

Answer 2

its answer 4?!

Answer 3

Yes, 4.