Sandra needs to obtain a random sample of 20 students from her school, in order to do a project for her statistics class. which method would be best for doing this? a) choose 20 students who are in sports programs. b) randomly select 10 girls and 10 boys from the girls' and boys' soccer teams. c) choose the first 20 students she sees in the hallway after leaving statistics class one day. d) at the next school assembly, choose one student from each of 20 randomly seleted rows of seats.