**Core Concept**
Sinusitis is a common inflammatory condition affecting the paranasal sinuses, typically caused by bacterial or viral infections. The symptoms of sinusitis can be broadly categorized into major and minor symptoms, with major symptoms being more severe and indicative of a significant infection.

**Why the Correct Answer is Right**
The major symptoms of sinusitis include facial pain or pressure, nasal congestion or blockage, nasal discharge or purulent rhinorrhea, and a decrease or loss of smell. These symptoms occur due to the inflammation and swelling of the mucous membranes lining the sinuses, which leads to obstruction of the sinus ostia and impaired drainage of mucus. The facial pain or pressure is caused by the inflammation of the periorbital and facial structures, while the nasal discharge or purulent rhinorrhea is a result of the increased production of mucus and the presence of bacteria or viruses.

**Why Each Wrong Option is Incorrect**
**Option A:** is not a major symptom of sinusitis, but it may be a symptom of sinusitis in some cases. However, it is not as specific or severe as the major symptoms listed above.
**Option B:** is not a major symptom of sinusitis. While fatigue can be a symptom of many conditions, it is not a specific or common symptom of sinusitis.
**Option C:** is not a major symptom of sinusitis. Although coughing can be a symptom of sinusitis, especially if there is postnasal drip, it is not as specific or severe as the major symptoms listed above.

**Clinical Pearl / High-Yield Fact**
It's essential to note that sinusitis can be acute or chronic, and the symptoms may vary depending on the duration and severity of the infection. A high index of suspicion is required to diagnose sinusitis, especially in patients with underlying conditions such as allergies or asthma.

**Correct Answer: D. None of the above.**