**Core Concept:** The correct preservation method for lung tissue during autopsy of suspected anaesthetic poisoning is crucial for histopathological examination and accurate diagnosis. Preservation methods should maintain tissue integrity and prevent degradation of vital molecules or structures. In the context of anaesthetic poisoning, preservation methods impact the detection of anaesthetic agents within lung tissue, allowing for accurate diagnosis and understanding of the pathological changes due to anaesthetic exposure.

**Why the Correct Answer is Right:** The correct answer is **C. Bouin's Solution (Trisodium Citrate, TSPP, and picric acid)**. Bouin's solution is a fixative solution that effectively preserves lung tissue for histopathological examination. The primary components, trisodium citrate (TSPP) and picric acid, work together to fix and stain proteins within the tissue, which enhances the visibility of cellular structures and allows for the detection of anaesthetic agents.

**Why Each Wrong Option is Incorrect:**

A. **Formalin (formaldehyde):** While formalin is a common fixative solution, it may cause tissue hardening and distortion, making it unsuitable for accurate examination of lung tissue in suspected anaesthetic poisoning cases.

B. **Carnoy's Solution:** Carnoy's solution primarily fixes tissues by alcohol and chloroform, which may not be effective in preserving lung tissue for anaesthetic agent detection.

D. **Bouin's Solution:** Although Bouin's solution is a correct answer, this explanation focuses on the more appropriate option, Bouin's solution (option C).

**Clinical Pearl:** When preparing lung tissue samples for autopsy in suspected anaesthetic poisoning cases, Bouin's solution (option C) is the optimal choice due to its effectiveness in preserving tissue structure and allowing for the detection of anaesthetic agents within the tissue. This knowledge is crucial for accurate diagnosis and understanding of the pathological changes caused by anaesthetic exposure.