Answer:
The sample must represent the target population
Explanation:
To figure out the answer to can eliminate the answers that don't make sense.
The question is A random sample of people is chosen to participate in a survey. For the survey results to be considered valid, which must be true of the random sample?
Lets look at our answers-
A: The sample must be the same size as the population.
That does not make sense as the answer because the sample doesn't always have to be the same size as the population. So let's cross that out.
B: The sample must represent the target population.
That Makes the most sense because if you have a survey and your trying to get people opinion the sample must represent the target.
C: The sample must be biased.
This answer also makes a bit sense but not as much as B.
D: The sample must be a group separate from the population.
This is wrong because if your trying to get multiple peoples opinion you don't need a specific or separate group from the population.
So, Our answer is B: The sample must represent the target.