In skinfold measurements, which of the following skinfolds is measured diagonally?

The chest skinfold is measured diagonally, making it the correct choice in this question. This measurement is taken at the midpoint of the distance between the anterior axillary line and the nipple for men, and at the distance from the anterior axillary line to the nipple for women. The diagonal approach is crucial because it allows for a more accurate assessment of subcutaneous fat in the chest area, reflecting the individual's overall body composition more effectively.

The other skinfold measurements, such as the triceps, abdomen, and thigh, are taken vertically. The triceps measurement is done on the back of the upper arm, the abdomen measurement is taken vertically just to the right of the umbilicus, and the thigh measurement is conducted on the front of the thigh. Each of these methods is standardized to ensure consistency and accuracy but do not employ the diagonal technique that is characteristic of the chest skinfold.