Question

structure that surrounds the heart (sac)
myocardium
endocardium
pericardium
epicardium

Explanation:

The pericardium is a double - walled sac that surrounds the heart. The myocardium is the muscular tissue of the heart, the endocardium is the inner lining of the heart chambers and valves, and the epicardium is part of the pericardium (the visceral layer of the serous pericardium). So the structure that surrounds the heart (sac) is the pericardium.

Answer:

C. Pericardium