**Core Concept**
The inguinal canal is a narrow passageway in the lower abdominal wall, allowing the spermatic cord in males and the round ligament of the uterus in females to pass through. The contents of the inguinal canal include the spermatic cord in males, the round ligament of the uterus in females, and the ilioinguinal nerve and the iliohypogastric nerve.

**Why the Correct Answer is Right**
The spermatic cord in males contains the vas deferens, testicular arteries, and pampiniform plexus of veins. In females, the round ligament of the uterus is a fibromuscular cord that extends from the uterus to the labia majora. The ilioinguinal nerve provides sensory innervation to the skin of the upper medial thigh and the root of the penis in males and the mons pubis and labia majora in females. The iliohypogastric nerve provides sensory innervation to the skin of the lower abdominal wall and the groin area.

**Why Each Wrong Option is Incorrect**
**Option A:** Not provided, but assuming it's one of the actual options, it should be a content of the inguinal canal.
**Option B:** Not provided, but assuming it's one of the actual options, it should be a content of the inguinal canal.
**Option C:** Not provided, but assuming it's one of the actual options, it should be a content of the inguinal canal.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the inguinal canal is a common site for hernias, particularly indirect inguinal hernias, which occur when part of the intestine protrudes through a weakness in the posterior wall of the inguinal canal.

**Correct Answer:** D