Muscle cells combine to form . A. muscle tissue

B. brain tissue

C. bone tissue

the answer is A

A. Muscle Tissue

Explanation:

Cells are the basis in creating tissues, which are the basis in creating organs, which are the basis in making the organ system.

In this case, the cells given to you are muscle cells. Using the description above, the next logical "upgrade" would be a muscle tissue, followed by a muscle, and then the muscular system.