## Core Concept
The question pertains to the appropriate container for sending vitreous samples for biochemical analysis. In clinical practice, the type of container used for collecting and transporting biological samples can significantly affect the accuracy of the test results, particularly for biochemical analyses.

## Why the Correct Answer is Right
The correct answer, **. Fluoride bottle**, is used for collecting samples for biochemical analysis, especially when the goal is to measure substances like glucose or alcohol levels. Fluoride helps in preserving the sample by inhibiting glycolysis (in the case of glucose measurement) and microbial growth, thereby ensuring the integrity of the biochemical constituents until analysis.

## Why Each Wrong Option is Incorrect
* **Option A: Plain tube** - A plain tube does not contain any additives and is not suitable for biochemical analyses where preservation of the sample is critical.
* **Option B: EDTA bottle** - EDTA (ethylenediaminetetraacetic acid) is an anticoagulant used primarily for hematological tests. It is not suitable for biochemical analysis of vitreous humor.
* **Option D: Lithium heparin bottle** - Lithium heparin is used as an anticoagulant for plasma determinations. It is not typically used for biochemical analysis of vitreous humor where fluoride is required for preservation.

## Clinical Pearl / High-Yield Fact
A key point to remember is that for postmortem biochemical analysis, especially in forensic pathology, vitreous humor can be a valuable specimen. The use of a fluoride bottle helps in accurate determination of substances like glucose and alcohol levels, which can be critical in certain investigations.

## Correct Answer: . Fluoride bottle