**Core Concept**
The question is testing knowledge of the characteristic radiographic findings in tuberculosis (TB). TB is a bacterial infection caused by Mycobacterium tuberculosis, which primarily affects the lungs but can also spread to other parts of the body. The characteristic imaging findings in TB are crucial for diagnosis and management.

**Why the Correct Answer is Right**
In pulmonary TB, the characteristic finding on CT is the Ghon complex, which consists of a combination of a peripheral pulmonary nodule or cavity, lymphadenopathy (enlarged lymph nodes), and fibrosis. The Ghon complex is formed by the primary infection site in the lung and the subsequent spread to the regional lymph nodes. The lymph nodes become enlarged and may calcify, while the lung parenchyma shows evidence of fibrosis and scarring.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is likely incorrect because it does not specify the characteristic findings of TB. TB can present with a wide range of radiographic findings, including cavitation, fibrosis, and lymphadenopathy, but this option is too vague.

**Option B:** This option may be incorrect because it does not accurately describe the characteristic findings of TB. While TB can cause pleural effusion, this is not a specific or characteristic finding of the disease.

**Option C:** This option may be incorrect because it does not accurately describe the characteristic findings of TB. While TB can cause bronchiectasis, this is more commonly associated with chronic infections such as cystic fibrosis.

**Clinical Pearl / High-Yield Fact**
The Ghon complex is a classic radiographic finding in pulmonary TB and is often seen in combination with lymphadenopathy and fibrosis. This finding is crucial for diagnosis and management of TB.

**Correct Answer: D. Ghon complex**