Which of the Following Is the Most Important Assumption for the Mark-Recapture

Which of the following is the most important assumption for the mark-recapture method to estimate the size of wildlife populations?

A) Marked individuals have the same probability of being recaptured as unmarked individuals during the recapture phase.
B) More than 50 percent of the marked individuals need to be trapped during the recapture phase.
C) More individuals emigrate from, as opposed to immigrate into, a population.
D) All females in the population have the same litter size.
E) There is a 50:50 ratio of males to females in the population before and after trapping and recapture.