Observe the given diagrammatic representation of a specific muscle tissue. Identify the structure labeled 'X' and select the option that correctly pairs it with the primary location of this tissue in the human body.

Step-by-step solution

Based on the diagrammatic representation, the muscle tissue shown has branched fibers, striations, and single, centrally located nuclei. These features are characteristic of cardiac muscle tissue. The structure labeled 'X' points to the dark, zig-zag bands connecting adjacent cardiac muscle cells. These are known as intercalated discs, which are specialized cell junctions containing desmosomes and gap junctions that allow the cardiac muscle cells to contract as a single functional unit. Cardiac muscle tissue is exc