Final answer:
The correct answer is option B. 35%, as nearly 36% of U.S. adults over 20 years old are reported to be obese. Additionally, to be classified as morbidly obese, an adult's BMI must be 40 or more.
Step-by-step explanation:
The percentage of adults in the United States who are obese is nearly 36%. To be more specific, by 2010, the U.S. Centers for Disease Control and Prevention reported that nearly 36% of adults over 20 years old were obese. This indicates that the correct answer to the student's question is option B. 35%. Obesity in the United States has been characterized as an epidemic, with rates steadily increasing since the 1980s. In addition to the obesity rates, approximately 33 percent of adults are considered overweight. With both obesity and overweight combined, over 70 percent of Americans are affected.
Regarding the classification of obesity, to be considered morbidly obese, an adult must have a Body Mass Index (BMI) of 40 or more, which corresponds to option D. 40 or more on the provided reference scale.