The correct response is:
The sample size of 400 will give a better approximation of population proportion, as it is symmetrical and the mean falls close to the middle of the distribution.
This statement is true as larger sample sizes tend to yield a sampling distribution that is closer to the true population proportion due to the law of large numbers. Larger samples reduce variability and result in a more accurate estimation of the population parameter, leading to a sampling distribution that is more symmetrical and concentrated around the true mean.