**Core Concept**
Mumps is a viral infection caused by the mumps virus, primarily affecting the salivary glands near the ears, leading to symptoms such as swelling, pain, and fever. The virus is highly contagious and can also affect other parts of the body, including the pancreas, ovaries, and testes.

**Why the Correct Answer is Right**
Mumps is characterized by the following features:
- Swelling of the parotid glands, which are the salivary glands located near the ears.
- Painful swelling in the cheeks and jaw area.
- Fever, headache, and muscle aches.
- Swollen and tender lymph nodes in the neck.
- In some cases, mumps can cause orchitis (inflammation of the testicles) in males and oophoritis (inflammation of the ovaries) in females.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because orchitis is a known complication of mumps, particularly in post-pubertal males. Orchitis can lead to testicular atrophy and infertility.

**Option B:** Incorrect because oophoritis is a known complication of mumps in females, which can lead to ovarian atrophy and infertility.

**Option C:** Incorrect because pancreatitis is a rare but serious complication of mumps, which can lead to abdominal pain, nausea, and vomiting.

**Clinical Pearl / High-Yield Fact**
Mumps is a vaccine-preventable disease, and the MMR (measles, mumps, and rubella) vaccine is effective in preventing mumps infection. However, two doses of the MMR vaccine are only about 88% effective in preventing mumps, which is why outbreaks can still occur in areas with low vaccination coverage.

**Correct Answer:** D.