Identify the type of sampling used in each of the following cases. 

a. The apple harvest from an orchard is collected in 1,200 baskets. An agricultural inspector randomly selects 25 baskets and then checks every apple in each of these baskets for worms. 

b. An educational researcher wants to know whether, at a particular college, men or women tend to ask more questions in class. Of the 10,000 students at the college, she interviews 50 randomly selected men and 50 randomly selected women. 

c. In trying to learn about planetary systems, astronomers conduct a survey by looking for planets among 100 nearby stars. 

d. To determine who will win autographed footballs, a computer program randomly selects the ticket numbers of 11 people in a stadium filled with people.