Body mass index bm is a measure of body weight relative to which factor

Body mass index is a measure of weight relative to the height of a person.it is calculated by obtaining the weight of a person in kilograms and dividing it by the square height in meters. It is widely used by medical, health and fitness professionals to classify underweight, overweight and obesity in adults. The BMI of a healthy weight individual should fall between 18.5 and 24.9, while a BMI below 18.5 is considered underweight, if it is greater than 25.0 then a person is said to be overweight while a score above 30 is considered Obese.

Answerfarmer's market; (b) would be my second choice