**Core Concept**
Transfusion-Related Acute Lung Injury (TRALI) is a serious complication of blood transfusion characterized by non-cardiogenic pulmonary edema. It occurs due to the transfusion of antibodies or biologically active lipids from the donor into the recipient's circulation, leading to activation of the complement system and leukocyte activation.

**Why the Correct Answer is Right**
TRALI typically occurs within 6 hours of transfusion, with most cases presenting within 2-4 hours. This is because the transfused antibodies or lipids need time to cause damage to the pulmonary endothelium and alveoli. The activation of the complement system and leukocyte activation leads to increased vascular permeability, resulting in fluid leakage into the alveoli and subsequent respiratory distress.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because TRALI can occur as early as 30 minutes to 1 hour after transfusion, but 6 hours is a more typical timeframe.
* **Option B:** This option is incorrect because TRALI can occur later than 6 hours after transfusion, but this is less common.
* **Option C:** This option is incorrect because TRALI can occur within 1-2 hours after transfusion, but 6 hours is a more typical timeframe.
* **Option D:** This option is incorrect because TRALI can occur within 30 minutes to 1 hour after transfusion, but 6 hours is a more typical timeframe.

**Clinical Pearl / High-Yield Fact**
It's essential to recognize that TRALI is often associated with the transfusion of female donor blood to male recipients, as female plasma contains more anti-HLA (human leukocyte antigen) and anti-neutrophil antibodies.

**Correct Answer: C. 6 hours.**