The brand manager for a brand of toothpaste must plan a campaign designed to increase brand recognition. He wants to first determine the percentage of adults who have heard of the brand. How many adults must he survey in order to be 95% confident that his estimate is within five percentage points of the true population percentage? Complete parts (a) through (c) below. a) Assume that nothing is known about the percentage of adults who have heard of the brand. n= (Round up to the nearest integer.) b) Assume that a recent survey suggests that about 77% of adults have heard of the brand. n = (Round up to the nearest integer.) c) Given that the required sample size is relatively small, could he simply survey the adults at the nearest college? O A. No, a sample of students at the nearest college is a stratified sample, not a simple random sample, so it is very possible that the results would not be representative of the population of adults. O B. Yes, a sample of students at the nearest college is a simple random sample, so the results should be representative of the population of adults. O C. No, a sample of students at the nearest college is a convenience sample, not a simple random sample, so it is very possible that the results would not be representative of the population of adults. O D. No, a sample of students at the nearest college is a cluster sample, not a simple random sample, so it is very possible that the results would not be representative of the population of adults