Kari plans to sample 20 people of a population that contains 100 students. She wants to determine how many people wake up before 6 a.m. Which sample is the most random?
the first 20 students who arrive at school in the morning
all 20 boys on the swim team
5 students out of each of the 4 homeroom classes
the last 20 people in line for breakfast in the cafeteria