A group of students in a seminar are interested in investigating what proportion of freshman students had visited the campus prior to enrolling. They interview a group of n = 25 freshman and find that 14 had made a visit to the campus. Since the sample size is small the confidence interval for p should.

a. use t* with degrees of freedom df = 24.
b. use z* with the plus four method.
c. Use all of the above.