**Core Concept**
The nasolacrimal duct is a critical structure in the lacrimal apparatus, responsible for draining tears from the eye into the nasal cavity. This is an essential component of the tear drainage system, which maintains ocular surface health by removing excess tears.

**Why the Correct Answer is Right**
The nasolacrimal duct opens into the inferior meatus of the nasal cavity, specifically through a valve-like structure called the lacrimal punctum. This anatomical arrangement allows tears to drain from the eye into the nasal cavity, where they can be absorbed or expelled. The opening of the nasolacrimal duct into the inferior meatus is a key feature of human anatomy, facilitating the efficient removal of excess tears and maintaining ocular surface health.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the nasolacrimal duct does not open into the maxillary sinus. While the maxillary sinus does receive drainage from the nasal cavity, it is not the direct recipient of tears from the nasolacrimal duct.
* **Option B:** This option is incorrect because the nasolacrimal duct does not open into the ethmoid sinus. The ethmoid sinus is a separate paranasal sinus that receives drainage from the nasal cavity, but it is not directly involved in tear drainage.
* **Option C:** This option is incorrect because the nasolacrimal duct does not open into the oral cavity. While the oral cavity is a common site for various bodily secretions, it is not the primary destination for tears from the nasolacrimal duct.

**Clinical Pearl / High-Yield Fact**
A key clinical correlation to remember is that blockage of the nasolacrimal duct can lead to epiphora (excessive tearing) and chronic eye irritation. This can occur due to various factors, including nasolacrimal duct obstruction, conjunctivitis, or other ocular surface disorders.

**Correct Answer: D. Inferior meatus of the nasal cavity.**