**Core Concept**
The retrobulbar block is a regional anesthesia technique used to anesthetize the eye. It involves injecting local anesthetic into the retrobulbar space to block the nerves supplying the eye. The **extraocular muscles** are responsible for eye movements.

**Why the Correct Answer is Right**
Since the question is incomplete, let's discuss the general concept. In a retrobulbar block, most extraocular muscles are paralyzed due to the blockage of nerves. However, the **superior tarsal muscle** (Müller's muscle) and the **inferior tarsal muscle**, which are responsible for eyelid elevation and are innervated by the sympathetic nervous system, are not completely paralyzed.

**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific option, it's challenging to provide a detailed explanation.
**Option B:** Typically, options that suggest paralysis of all extraocular muscles would be incorrect because some muscles, like those innervated by the sympathetic nervous system, are not completely paralyzed.
**Option C:** Similar to Option A, without the specific text, it's difficult to provide a precise explanation.
**Option D:** This option would be incorrect if it suggested that a muscle primarily responsible for eye movement was not paralyzed.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the retrobulbar block can cause **ptosis** (drooping of the eyelid) due to the paralysis of the extraocular muscles, but the extent of muscle paralysis can vary based on the block's effectiveness and the specific anatomy of the individual.

**Correct Answer:** D. Superior tarsal muscle