**Core Concept**
The cremasteric reflex is a physiological reflex that involves the contraction of the cremaster muscle in response to stroking the skin of the upper inner thigh, which helps to regulate testicular temperature. This reflex is mediated by the somatic nervous system and involves the transmission of afferent and efferent impulses through specific nerves.

**Why the Correct Answer is Right**
The afferent impulses of the cremasteric reflex are transmitted through the ilioinguinal nerve, which provides sensory innervation to the upper inner thigh. The ilioinguinal nerve arises from the L1 spinal nerve and follows a course that allows it to innervate the cremaster muscle. When the skin of the upper inner thigh is stroked, the afferent impulses are transmitted to the spinal cord, where they are processed and result in the contraction of the cremaster muscle.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the femoral nerve primarily provides motor innervation to the quadriceps muscle and does not transmit afferent impulses related to the cremasteric reflex.
**Option B:** This option is incorrect because the obturator nerve primarily provides motor innervation to the adductor muscles of the thigh and does not transmit afferent impulses related to the cremasteric reflex.
**Option C:** This option is incorrect because the genitofemoral nerve primarily provides motor innervation to the cremaster muscle, but it is not responsible for transmitting afferent impulses related to the cremasteric reflex.

**Clinical Pearl / High-Yield Fact**
The cremasteric reflex is an important clinical sign that can be used to assess the integrity of the somatic nervous system and the function of the cremaster muscle. Abnormalities in this reflex can indicate a variety of conditions, including testicular torsion or epididymitis.

**Correct Answer: C. genitofemoral nerve**