Final answer:
The trunk flexors (abdominal muscles) would be the most likely overlengthened muscle group that requires strengthening in a person with a chronic excessive anterior tilt posture. Hence the correct answer is option C
Step-by-step explanation:
In a person who displays a chronic excessive anterior tilt posture, the trunk flexors (abdominal muscles) would be the most likely muscle group to be overlengthened and would require strengthening. This is because the anterior tilt posture is characterized by an increased arch in the lower back, which indicates weakness in the abdominal muscles. By strengthening the trunk flexors, the person can help restore a more balanced posture and reduce excessive anterior tilt.
Hence the correct answer is option C