Which statement would the information presented in this population pyramid best justify?

a: nigeria will need outside immigration to keep its population stable.
b: women in nigeria are having more children today than they used to in the past.
c: nigeria has a faster rate of growth than any of its neighbors.
d: there will be over one billion people in nigeria by 2015.

Since ages in a population pyramid are represented ranging from youngest at the bottom to oldest at the top, the two graphs aligned side by side typically give the appearance of a pyramid. This is because fewer people in a population live into old age. The BBC notes, however, that it is possible to distinguish different qualities in a population through variations from the standard pyramid shape. For example, an aging population with a low birth rate would look like an upside-down pyramid.