**Core Concept**
A chalazion is a type of benign eyelid lesion resulting from the blockage of a meibomian gland, leading to inflammation and the formation of a granulomatous nodule. The meibomian glands are responsible for the production of meibum, an oily substance that helps to lubricate the eyelid.

**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of a chalazion. A chalazion occurs when a meibomian gland becomes obstructed, causing the gland to become inflamed and form a granulomatous nodule. This obstruction can be due to various factors, including meibomian gland dysfunction, which is characterized by the abnormal expression of meibum and the presence of meibomian gland orifices that are too small to allow for proper drainage.

**Why Each Wrong Option is Incorrect**
* **Option A:** This statement is incorrect because a chalazion is not caused by an infection. While a chalazion can become secondarily infected, the primary cause is the blockage of a meibomian gland.
* **Option B:** This statement is incorrect because a stye (hordeolum) is a different type of eyelid lesion that is caused by an infection of the eyelid margin. While both a chalazion and a stye can present as a red, painful nodule on the eyelid, they have distinct underlying causes.
* **Option C:** This statement is incorrect because a chalazion does not typically result from a foreign body in the eyelid. While a foreign body can cause an inflammatory reaction in the eyelid, it is not a common cause of a chalazion.

**Clinical Pearl / High-Yield Fact**
A key feature of a chalazion is that it is typically painless, whereas a stye (hordeolum) is often painful. This is because a chalazion is caused by the blockage of a meibomian gland, which is a benign process, whereas a stye is caused by an infection of the eyelid margin.

**Correct Answer:** D.