Match the following columns correctly.

Column-$I$	Column-$II$
$(a)$ Population density	$(i)$ Demography
$(b)$ Natality	$(ii)$ Birth rate
$(c)$ Mortality	$(iii)$ Population decline
$(d)$ Demography	$(iv)$ Total number of individuals per unit area and unit volume

• A
  $(a-iv), (b-ii), (c-iii), (d-i)$
• B
  $(a-i), (b-ii), (c-iii), (d-iv)$
• C
  $(a-ii), (b-i), (c-iv), (d-iii)$
• D
  $(a-iii), (b-iv), (c-i), (d-ii)$