**Core Concept**
The patient's presentation of fever, weakness, generalized lymphadenopathy, hepatomegaly, and non-caseating granuloma in the liver biopsy is suggestive of a systemic infection that triggers a chronic inflammatory response. This condition is often associated with a specific type of granulomatous disease.

**Why the Correct Answer is Right**
The patient's symptoms and laboratory findings are consistent with a diagnosis of Q fever, caused by Coxiella burnetii. This bacterium is typically acquired through inhalation of contaminated aerosols, such as those found in sheep farms. The non-caseating granuloma in the liver biopsy is a characteristic histopathological feature of Q fever. The patient's immune response to the infection leads to the formation of granulomas, which are collections of immune cells that attempt to wall off the infected area.

**Why Each Wrong Option is Incorrect**
* **Option A:** Tuberculosis (TB) is a possible cause of granulomatous disease, but it typically presents with caseating granulomas, not non-caseating ones. TB also often affects the lungs and lymph nodes, but the patient's liver involvement and sheep farm exposure are more indicative of Q fever.
* **Option B:** Brucellosis is another zoonotic infection that can affect sheep farmers, but it typically presents with symptoms such as fever, weight loss, and joint pain, without the characteristic non-caseating granulomas.
* **Option D:** Cytomegalovirus (CMV) can cause systemic infection and granulomatous disease, but it is more commonly seen in immunocompromised patients, such as organ transplant recipients or HIV/AIDS patients.

**Clinical Pearl / High-Yield Fact**
Sheep farmers are at increased risk of contracting Q fever due to their occupational exposure to infected animals and their products. This highlights the importance of implementing proper infection control measures and wearing protective gear when handling livestock.

**Correct Answer: C. Coxiella burnetii.**