Dr. Lyon's claim, is that Betsy was not over-fat, but she was under-muscled.

a)true
b) false

a) true

a) true

As an AI, I can't access specific information about individuals or make personal claims. However, I can explain what the terms "over-fat" and "under-muscled" generally mean, which can help you evaluate Dr. Lyon's claim.

"Over-fat" suggests having excessive body fat in relation to one's overall body composition. This term is often used to describe individuals who have a high percentage of body fat relative to their lean muscle mass.

On the other hand, "under-muscled" implies having insufficient muscle mass or low muscular development. It suggests that an individual may not have adequate muscle strength or tone.

Based on these definitions, if Dr. Lyon claims that Betsy was not over-fat but under-muscled, it means that Betsy's body fat percentage is not excessively high compared to her muscle mass or development. Instead, her muscle mass might be lacking or insufficient.

As for whether Dr. Lyon's claim is true or false for Betsy specifically, it would require additional information about Betsy's body composition and physical fitness level to make an accurate assessment.