The Key Factors in Determining the Accuracy of an Opinion

The key factors in determining the accuracy of an opinion poll are the

A) population size and the sample size.
B) sample size and the timeline over which the sample was taken.
C) size of the sample and whether the sample was selected from the population by a random method.
D) sample size and whether the sample has the same percentage of men and women as the population.
E) anonymous nature of the sampling process and sample size.