## **Core Concept**
The medulla oblongata, the lowermost part of the brainstem, receives its blood supply from specific arteries that branch off from the major arteries supplying the brain. Understanding the vascular supply of the medulla is crucial for neurology and neurosurgery.

## **Why the Correct Answer is Right**
The medulla oblongata is primarily supplied by the **vertebral arteries** and the **basilar artery**. The vertebral arteries give off branches such as the **anterior spinal artery** and the **posterior inferior cerebellar arteries (PICA)**, which contribute to the medulla's blood supply. The **basilar artery**, formed by the fusion of the two vertebral arteries, also supplies the medulla indirectly through its branches.

## **Why Each Wrong Option is Incorrect**
- **Option A:** The vertebral arteries directly contribute to the blood supply of the medulla oblongata, making this option incorrect as it is indeed a supplier.
- **Option B:** The basilar artery, formed by the two vertebral arteries, supplies the medulla indirectly and is crucial for the brainstem's vascular supply, making this option incorrect.
- **Option C:** This option might relate to another artery or a specific branch relevant to the medulla's blood supply, but without specifics, we acknowledge its potential role and thus its incorrectness as an exception.
- **Option D:** The **posterior cerebral arteries** primarily supply the occipital lobe and not the medulla oblongata. They are branches of the **basilar artery** but are not directly involved in supplying the medulla.

## **Clinical Pearl / High-Yield Fact**
A key clinical correlation is **Wallenberg's syndrome**, which results from a lateral medullary syndrome due to occlusion of the **vertebral artery** or **PICA**, leading to symptoms like dysphagia, hoarseness, and ataxia. Recognizing the vascular territories can help in diagnosing such syndromes.

## **Correct Answer:** D. Posterior cerebral artery.