**Core Concept:**
The right hypoglossal nucleus is a part of the central nervous system that controls the movement of the tongue muscles. The hypoglossal nerve (CN XII) originates from the hypoglossal nucleus and supplies motor innervation to the muscles of the tongue. Lesions in this region can lead to tongue movement problems.

**Why the Correct Answer is Right:**
In a healthy individual, the right hypoglossal nucleus controls the movement of the right half of the tongue. When there is a lesion in the right hypoglossal nucleus, the output of the nerve is impaired, leading to weakness or inability to control the corresponding side of the tongue. In this case, the correct answer is "A," as the lesion would result in the inability to protrude the tongue on the affected side.

**Why Each Wrong Option is Incorrect:**
B and D are incorrect because they refer to the left side of the tongue, which is controlled by the left hypoglossal nucleus and its corresponding hypoglossal nerve. C is incorrect because it refers to a lateral tongue deviation, which is not related to the hypoglossal nucleus.

**Clinical Pearl:**
Understanding the anatomy and function of cranial nerves is crucial for diagnosing and treating various neurological disorders. In clinical practice, a patient presenting with difficulty in protruding the tongue on one side might have a lesion affecting the hypoglossal nucleus or its pathway, highlighting the importance of considering this diagnosis when evaluating patients with tongue movement disorders.