Answer:
C, basic contractile unit of muscle fiber.
Step-by-step explanation:
If you read the definition of sarcomere, this is what it says: "A sarcomere (Greek σάρξ sarx "flesh", μέρος meros "part") is the complicated unit of striated muscle tissue. It is the repeating unit between two Z lines. Skeletal muscles are composed of tubular muscle cells (myocytes called muscle fibers or myofibers) which are formed in a process known as myogenesis."
hope this helps.