Relative strength is the magnitude of the force: d) per 1 kilogram of the athlete's weight.
Relative strength can be defined as the total amount of weight that a person's body such as athlete can lift, relative to his or her body weight.
This ultimately implies that, relative strength refers to the amount of strength that a person such as an athlete possess when compared to his or her body weight. Also, it is a measure of how strong a person is compared to their his or her body weight (size).
In conclusion, relative strength is the magnitude of the force per 1 kilogram of an athlete's body weight (size).
Read more on force here: brainly.com/question/1121817