Answer:
Option C, the comparative sizes of the male and female populations
Step-by-step explanation:
Demographers very frequently use age structure diagram also known as population pyramid as a tool to understand the distribution of population into two groups i.e male and female population along with details of age.
The pyramid diagram is generally of three type -
a) Progressive - growing population
b) Stagnant - stagnant population
c) Degenerative - decreasing population
Hence, option C is correct