Ben Wanted to Know How Many College Students Living in the Dorms

Ben wanted to know how many college students living in the dorms subscribed to a streaming service such as Netflix, but he couldn't survey every one of them. Ben decided that in order to give all students an equal chance of being selected to participate in his mini study, he would visit the dorms at dinnertime and ask them to choose numbers out of a hat. The ones with the number 7 were given a quick three-question survey. Ben is demonstrating

A) nonprobability sampling.
B) biased sampling.
C) equal opportunity sampling.
D) simple random sampling.
E) snowball sampling.