74% of the 398 student who attended the October 15th lecture said they know how to "explain correctly a confidence statement". If these 398 were a simple random sample drawn from the entire UK student population, and the 95% confidence interval is 74%+/-5%, in which of these cases would the confidence interval be wider than the one calculated?
a) The sample size increases to 600 students.
b) The sample proportion decreases to 70%.
c) The sample proportion increases to 80%.
d) The confidence level decreases to 90%.
