Can you help me?

a college plannes to sample 100 students to construct a 9% confidence interval for the mean mathematics ACT score for all students at the college. Tp save time and money they coose to sample only 50studets instead of 100 students, what effect will this have on the width (margin of error) of the confidence interval

Answers:

a. The margin of error would have been larger when the sample size was 100

b. The margin of error will be smaller if the sample size is 50

c. If everything else remains the same, the margin of error will be the same regardless of the sample size.

d. The margin of error will be larger if the sample size is 50

e. None of these