A group of identical quintuplets named Aaron, Bill, Carl, Dave, and Ed enjoy confusing the teachers at

Question:

A group of identical quintuplets named Aaron, Bill, Carl, Dave, and Ed enjoy confusing the teachers at their school. List the number of different possibilities in each case, and then count them up. Make sure your counts match the appropriate value of "n choose k."
1. Only one goes to school.
2. Two go to school.
3. Three go to school.
4. Four go to school.