**Core Concept**
Recurrent pulmonary consolidation in a child, especially in one lobe, may suggest a bronchiolar obstruction or a congenital anomaly leading to abnormal drainage of lung segments.

**Why the Correct Answer is Right**
The clinical presentation of recurrent consolidation in the right lower lobe, despite initial improvement with antibiotics, raises the suspicion of a congenital anomaly or a foreign body leading to bronchiolar obstruction. The increasing consolidation suggests an incomplete resolution of the initial infection, possibly due to the abnormal drainage of lung segments.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because a simple viral or bacterial pneumonia would not recur in the same lobe without any predisposing factor.
* **Option B:** This option is incorrect because a chest CT scan may be useful in identifying some congenital anomalies, but it is not the next investigation in this scenario.
* **Option C:** This option is incorrect because bronchoscopy is an invasive procedure and would not be the first line of investigation in this case.

**Clinical Pearl / High-Yield Fact**
In children, recurrent pulmonary consolidation in one lobe should prompt a search for congenital anomalies, foreign bodies, or abnormal lung drainage patterns.

**Correct Answer: D. Bronchogram**