Final answer:
The longissimus dorsi muscle is the most tender muscle in comparison.
Step-by-step explanation:
The correct answer is A) Longissimus dorsi. The longissimus dorsi muscle is a broad, triangular muscle located on the inferior part of the back. It extends from the lower back to the neck and is responsible for extending and laterally flexing the spine. The trapezius muscle, on the other hand, is a large, triangular muscle located on the upper back and neck. It is involved in moving and stabilizing the shoulder blades and neck. The rectus femoris is a muscle in the thigh that is responsible for extending the leg at the knee joint. Therefore, out of the given options, the longissimus dorsi muscle is the most tender muscle in comparison.