The correct option is
C Almost equal to base
Population pyramid: a pyramid-shaped diagram illustrating the age distribution of a population. The youngest is represented by a rectangle at the base, the oldest by one at the apex. The apex of a diminishing population is broad and an expanding population is narrow, whereas in a stabilized population it is only smaller than pre-reproductive and reproductive age groups.
Stable pyramid: A population pyramid showing an unchanging pattern of fertility and mortality.
Stationary pyramid: A population pyramid typical of countries with low fertility and low mortality, very similar to a constrictive pyramid.
Expansive pyramid: A population pyramid that is very wide at the base, indicating high birth and death rates.
Constrictive pyramid: A population pyramid that comes in at the bottom. The population is generally older on average, as the country has a long life expectancy, a low death rate, but also a low birth rate. This pyramid is becoming more common, especially when immigrants are factored out, and is a typical pattern for a very developed country, a high level of education, easy access to and incentive to use birth control, good health care, and few negative environmental factors.