This is the role of the coronary artery

The correct option is "to supply blood to heart muscles".

Here is a step-by-step explanation of why this is correct:

1. Understanding the Heart's Function: The heart is a muscular organ that pumps blood to the entire body. However, because it is constantly working, the heart muscle itself (myocardium) requires a continuous supply of oxygen and nutrients to function effectively.

2. The Role of Coronary Arteries: The coronary arteries branch off from the aorta, which is the main artery carrying oxygen-rich blood away from the heart. Instead of heading to the rest of the body, these coronary arteries wrap around the exterior of the heart to deliver oxygenated, nutrient-rich blood directly to the heart muscles.

3. Distinguishing Options:
- Carrying blood away from the heart muscles is primarily the role of coronary veins.
- Supplying blood to all parts of the body is the role of the systemic circulation (via the aorta and its larger branches).
- Therefore, the specific function of the coronary artery is to supply blood directly to the heart muscles.