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

A. the sample size and whether the sample has the same percentage of men and women as the population.

B. the size of the sample and whether the sample was selected from the population by a random method.

C. the population size and the sample size.

D. the sample size and the timeline over which the sample was taken.

E. the anonymous nature of the sampling process and sample size.

Option B

Step-by-step explanation:

In this case, rather than tell you why option B is correct, let me tell you why the other options are incorrect.

As you can see, all the options share one common answer and is the sample size, so, this is one of the first key factors.

In option A, you have same percentage of men and women. This is not true, because the poll can be used only by men or women, so the percentage of men and women are not factors here.

In option C, we only have the population size. This is not accurate because, because we can determine the accuracy of the poll whether you have a population size of 20 people, and get the same accuracy with a population size of 100.

In option D, it's not neccesary the timeline, because you can take the accuracy in one time, and the result will be the same after time, for example, suppose the opinion poll is about politic, and the question is whether you liked Trump at the beggining or not. You could answer no at first, and say no again, 5 years later if the question remains the same.

Finally option E, you don't need to know the nature of the sampling process to get the accuracy of the poll.

The most important here is which method was taken to do the poll, for example, if it was oral, written or other method.