Scientists Were Interested in Determining Whether There Is a Relationship

Scientists were interested in determining whether there is a relationship between cancer and BMI.So they recorded the BMI of over 100,000 cancer-free people and then tracked them for 15 years.The results are shown below: BMI < 25 Relative risk = 1.0
BMI 25-29.9 Relative risk = 1.3
BMI >30 Relative risk =1.7
Which statement best describes the experiment and its results?

A) It is an observational study that suggests that cancer risk increases as body weight increase.
B) It is an intervention trial that suggests that cancer risk increases as body weight increase.
C) It is an observational study that suggests that cancer risk decrease as body weight increases.
D) It is an intervention trial that suggests that cancer risk decrease as body weight increases.