Does Regular Exercise Decrease the Risk of Cancer? a Researcher

Does regular exercise decrease the risk of cancer? A researcher finds 200 women over 50 who
Exercise regularly, pairs each with a woman who has a similar medical history but does not
Exercise, then follows subjects for 10 years to see which group develops more cancer. This is a

A) survey
B) retrospective study
C) matched experiment
D) randomized experiment
E) prospective study