**Core Concept**
Secondary deviation of the eye in strabismus refers to the occurrence of a larger angle of deviation between the two eyes when the fixing eye is changed from one eye to the other, indicating a lack of binocular vision control. This phenomenon is a result of the suppression of vision in the deviating eye, leading to a loss of fusion and binocular vision control.

**Why the Correct Answer is Right**
The correct answer is related to the concept of suppression, which is a protective mechanism that the brain uses to prevent the stimulation of both eyes simultaneously when they are not aligned properly. In strabismus, the brain suppresses the image from the deviating eye to prevent diplopia (double vision). When the fixing eye is changed, the brain no longer has the same level of control over the binocular vision, resulting in a larger angle of deviation, known as secondary deviation.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because secondary deviation is not related to the innervation of the extraocular muscles.
* **Option B:** This option is incorrect because secondary deviation is not a result of the paralysis of the extraocular muscles.
* **Option C:** This option is incorrect because secondary deviation is not related to the alignment of the eyes in the primary position.

**Clinical Pearl / High-Yield Fact**
It is essential to note that secondary deviation is a critical indicator of the presence of strabismus and a lack of binocular vision control. A thorough understanding of this concept is crucial for ophthalmologists and orthoptists to diagnose and manage strabismus effectively.

**Correct Answer: C. Alignment of eyes.