Final answer:
The posterior descending artery (PDA) and the acute marginal branch form the b) coronary artery.
Step-by-step explanation:
The coronary artery system is crucial for supplying blood to the heart muscle. The posterior descending artery (PDA) and acute marginal branch are integral components of this network. The PDA, a branch of the right coronary artery, travels along the posterior interventricular sulcus, supplying the posterior and inferior parts of the heart.
On the other hand, the acute marginal branch, arising from the right coronary artery, serves the right atrium and ventricle. Together, these arteries play a vital role in ensuring the heart receives oxygenated blood, sustaining its continuous and coordinated pumping action for the body's circulatory needs.