**Core Concept**
The question tests the management of a life-threatening complication of blood transfusion, specifically Transfusion-Related Acute Lung Injury (TRALI). TRALI is characterized by non-cardiogenic pulmonary edema, hypoxemia, and bilateral infiltrates on chest radiographs, typically occurring within 6 hours of transfusion.

**Why the Correct Answer is Right**
TRALI is a result of the interaction between the transfused blood components and the recipient's immune system, leading to the activation of neutrophils and the release of inflammatory mediators. This results in the disruption of the alveolar-capillary membrane, causing fluid leakage into the alveoli. The management of TRALI involves the immediate cessation of the transfusion, as continuing it can exacerbate the condition. The focus shifts to supportive care, including mechanical ventilation, to manage the respiratory distress.

**Why Each Wrong Option is Incorrect**
* **Option A:** Continuing the transfusion would worsen TRALI, making antihistamines ineffective in addressing the underlying issue.
* **Option B:** Administering a diuretic is not indicated in TRALI, as the pulmonary edema is not due to volume overload.
* **Option C:** Performing bronchoscopy and initiating broad-spectrum antibiotics may be useful in diagnosing and treating other causes of respiratory distress, but they do not address the primary issue of TRALI.

**Clinical Pearl / High-Yield Fact**
TRALI is the leading cause of transfusion-related mortality, accounting for approximately 5% of all transfusion-related deaths. Recognizing the clinical presentation of TRALI and promptly discontinuing the transfusion are crucial in preventing further complications.

✓ Correct Answer: D. Stop the transfusion and continue supportive respiratory care.