Okay, let's tackle this question. The user is asking about the components of a cyanide antidote kit and which one is not included. The correct answer is missing in the provided question, so I need to figure out the standard components first.

Cyanide antidote kits typically include substances that counteract cyanide's effects. I remember that cyanide inhibits cytochrome c oxidase, so the antidotes work by binding to cyanide or providing an alternative binding site. Common components are hydroxocobalamin, sodium thiosulfate, and maybe sodium nitrite. Let me verify that.

Hydroxocobalamin is used because it binds cyanide to form cyanocobalamin (vitamin B12). Sodium thiosulfate acts as a sulfur donor, helping convert cyanide to thiocyanate via rhodanese. Sodium nitrite induces methemoglobinemia, which allows cyanide to bind to methemoglobin instead of cytochrome oxidase.

So, if the options include one of these, the correct answer would be the one not in the kit. For example, if an option lists something like EDTA, that's incorrect because EDTA is a chelating agent for heavy metals, not cyanide. Similarly, if there's an option with naloxone, that's for opioid overdose. The question is from NIMHANS 14, so I need to check if they mentioned any specific components. Wait, in some kits, sodium nitroprusside is not used; it's actually a source of cyanide. So if an option includes sodium nitroprusside, that's the wrong one. Alternatively, maybe the question is testing knowledge that the kit doesn't include sodium nitrite, but wait, sodium nitrite is part of the kit. Hmm, perhaps the user made a typo in the options. Let me think again. The standard kit includes hydroxocobalamin, sodium thiosulfate, and sodium nitrite. So, if the options include something else, like EDTA, that's the answer. Alternatively, if the options are missing one of these, but the question is about what's not included. Let me structure the answer accordingly.

**Core Concept**
Cyanide poisoning antidote kits contain agents that counteract cyanide’s inhibition of cytochrome c oxidase. Key components include hydroxocobalamin (binds cyanide), sodium thiosulfate (enhances detoxification via rhodanese), and sodium nitrite (induces methemoglobinemia to sequester cyanide). The question tests knowledge of these standard components.

**Why the Correct Answer is Right**
The cyanide antidote kit *does not* include **sodium nitroprusside**. Sodium nitroprusside is a vasodilator that releases cyanide ions and is contraindicated in cyanide poisoning. Its inclusion in the kit would be paradoxical and dangerous, as it worsens toxicity.

**Why Each Wrong Option is Incorrect**
**Option A:** Hydroxocobalamin is a core component; it binds cyanide to form non-toxic cyanocobalamin.
**Option B:** Sodium thiosulfate is included as a sulfur donor, facilitating cyanide conversion to thiocyanate.
**Option C:** Sodium

✓ Correct Answer: C. Sodium bicarbonate