Answer:
A) The greater the variance within the population, the larger the sample should be.
Explanation:
The variance of a sample mean is inversely proportional to the sample size, that is, the larger the sample size the smaller the variability of the sample. When sample size increases, the range decreases and hence the variance decreases resulting in a more accurate research result with minimal experimental error.
Hence the researcher should employ a large sample size to reduce the variation in the population.