The 2011 National Youth Risk Behavior Survey provides insight on the physical activity of high school students in the United States. More than 15,000 high schoolers were asked, "During the past 7 days, on how many days were you physically active for a total of at least 60 minutes per day?" Physical activity was defined as any activity that increased heart rate. Let X represent the response. The survey results are given for the probability model for X.Days 0 1 2 3 4 5 6 7Probability 0.15 0.08 0.10 0.11 0.10 0.12 0.07 0.27(a) Which of the statements verifies why this a legitimate discrete probability model?The eight probabilities have sum 1 (and account for all possible responses to the question).The eight probabilities have sum 0 (and account for all possible responses to the question).The eight probabilities have sum 1 (and account for all possible responses to the question).