Where does the myocardium receives oxygenated blood from?
Coronary arteries supply oxygenated blood to the heart muscle, and cardiac veins drain away the blood once it has been deoxygenated. 
What arteries do the myocardium receive oxygenated blood from?
Coronary arteries
Coronary circulation
No context provided
What organs do the myocardium receive oxygenated blood from?
Lungs
Coronary circulation
https://en.wikipedia.org/wiki/Coronary%20circulation
Cardiac muscle (also called heart muscle or myocardium) is one of three types of vertebrate muscle tissue,
Cardiac muscle
The pulmonary circulation carries deoxygenated blood from the heart to the lungs and returns the oxygenated blood to the heart to supply the rest of the body.
Lung
Deoxygenated blood leaves the heart, goes to the lungs, and then re-enters the heart
Pulmonary circulation
Coronary arteries supply oxygenated blood to the myocardium or heart muscle, and cardiac veins drain away the blood once it has been deoxygenated. This deoxygenated blood leaves the heart, goes to the lungs, and then re-enters the heart as oxygenated blood to supply the rest of the body.