Question

what muscle is m? trapezius gluteus maximus latissimus dorsi gastrocnemius

Explanation:

The latissimus dorsi is a large, flat muscle that covers the lower back. It is located in the area typically labeled as "M" in such anatomical diagrams. The trapezius (A in the diagram) is in the upper back/neck area, the gluteus maximus is in the buttock region, and the gastrocnemius is a calf muscle.

Answer:

latissimus dorsi