**Core Concept**
Sixth nerve palsy, also known as abducens nerve palsy, involves the unilateral or bilateral dysfunction of the abducens nerve (cranial nerve VI), which is responsible for controlling lateral rectus muscle. This leads to impaired eye movement in the affected eye.

**Why the Correct Answer is Right**
The clinical features of sixth nerve palsy include lateral rectus muscle weakness, resulting in impaired abduction of the affected eye. This leads to esotropia (inward turning of the eye) or hypertropia (elevation of the eye) in the affected eye, which can be accompanied by head tilt or face turn to compensate for the impaired eye movement. The affected eye may also show a "pursuit lag" or "catch-up saccade" when attempting to track a moving object.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the clinical features of sixth nerve palsy.
**Option B:** This option may be related to a different cranial nerve palsy, such as third nerve palsy (oculomotor nerve).
**Option C:** This option is not specific to sixth nerve palsy and may be seen in other conditions affecting eye movement.

**Clinical Pearl / High-Yield Fact**
In sixth nerve palsy, the affected eye may show a characteristic "abduction lag" or "pursuit lag" when attempting to track a moving object, which is a key differentiating feature from other forms of strabismus.

**Correct Answer: C. Esotropia or hypertropia of the affected eye.**