Assume that when human resource managers are randomly​ selected, 38​% say job applicants should follow up within two weeks. If 6 human resource managers are randomly​ selected, find the probability
a) that exactly 4 of them say job applicants should follow up within two weeks.
b) that exactly all of them say job applicants should follow up within two weeks.
c) that at least 4 of them say job applicants should follow up within two weeks.