A group of statistics students conducted a survey about smoking habits on campus to determine the proportion of students who believe that smoking hookah (a water pipe) is less harmful than smoking cigarettes. Of the 50 students surveyed, 45 think that smoking hookah is less harmful than smoking cigarettes.
Which of the following is a reason that this group of students should not calculate a confidence interval for the proportion of all students who believe that smoking hookah is less harmful than smoking cigarettes? Check all that apply.

a) The sample needs to be random but we don’t know if it is.
b) The actual count of students who believe that smoking hookah is less harmful than smoking cigarettes is too small.
c) The actual count of students who do not believe that smoking hookah is less harmful than smoking cigarettes is too small.
d) n(p^) is not greater than 10.
e) n(1 - p^) is not greater than 10.