Final answer:
The blood vessel that becomes blocked and leads to an acute myocardial infarction, or heart attack, in a 56-year-old man is the coronary artery.
Step-by-step explanation:
In the case of a 56-year-old man with an acute myocardial infarction (heart attack), the blood vessel that became blocked and led to his condition is the coronary artery. The coronary arteries are blood vessels that supply the heart muscle with oxygenated blood. When a coronary artery becomes blocked, it restricts blood flow to the heart muscle, causing the heart muscle cells to die and resulting in a heart attack.
A 56-year-old man has an acute myocardial infarction, commonly known as a heart attack. The blood vessel that commonly becomes blocked in such a condition is the coronary artery. Coronary arteries supply the heart muscle with the blood that is rich in oxygen, and blockages in these arteries, caused by atherosclerosis, can prevent oxygen from getting to parts of the heart. This leads to ischemia or infarction, where the deprived areas of the heart muscle begin to die. So, the correct answer to which blood vessel became blocked and led to his condition is A) Coronary artery.