**Core Concept**
The underlying principle being tested is the understanding of **orbital fractures** and their effects on **extraocular muscle** function. This involves knowledge of **anatomy** of the orbit and the relationship between the eye and surrounding structures.

**Why the Correct Answer is Right**
The clinical presentation suggests a **blowout fracture** of the orbit, where the force of the impact causes a fracture of the orbital floor or medial wall, leading to entrapment of the **inferior rectus muscle** or **medial rectus muscle**. This results in restriction of **lateral and upward gaze** and **diplopia**. The presence of **enophthalmos** supports this diagnosis, as it indicates posterior displacement of the globe.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not typically present with restriction of lateral gaze.
**Option B:** This option is incorrect because it is not directly related to the symptoms described.
**Option C:** This option is incorrect because it would not cause the specific pattern of diplopia and gaze restriction seen in this patient.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that **blowout fractures** can present with **limited extraocular muscle movement** and **diplopia**, even in the absence of obvious eye injury.

**Correct Answer:** D. Blowout fracture of the orbit.