**Core Concept**
The yoke muscle pair in ophthalmology refers to two extraocular muscles that work in opposition to maintain gaze stability and enable smooth eye movements. These muscles are paired based on their origin and action, with one muscle on each side of the body acting in a coordinated manner to control eye movement.

**Why the Correct Answer is Right**
The right lateral rectus (Rt LR) and left medial rectus (Lt MR) form a yoke muscle pair. These muscles act in opposition during horizontal gaze movements: the lateral rectus abducts the eye, while the medial rectus adducts it. The pairing ensures balanced movement and prevents torsion. The yoke mechanism is essential for maintaining binocular vision and gaze stability.

**Why Each Wrong Option is Incorrect**
Option A: Rt LR and Rt MR are not a yoke pair; they are on the same side and act in opposite directions, not in opposition across the midline.
Option B: Rt SO and Lt IO are not yoke pairs; the superior oblique and inferior oblique are not paired in this manner and do not function as a coordinated yoke system.
Option D: "All the above" is incorrect because only option C correctly identifies a true yoke pair.

**Clinical Pearl / High-Yield Fact**
The yoke muscle pair (Rt LR and Lt MR) is critical in horizontal gaze control; understanding this pairing helps in diagnosing cranial nerve palsy and assessing eye movement disorders.

✓ Correct Answer: C. Rt LR and Lt MR