**Core Concept**
Cyanide is a potent toxin that disrupts cellular respiration by targeting the electron transport chain (ETC) in mitochondria. It binds to cytochrome c oxidase (Complex IV), preventing the transfer of electrons and thus inhibiting the production of ATP.

**Why the Correct Answer is Right**
Cyanide binds to the iron atom in the heme group of cytochrome c oxidase, forming a stable complex that cannot be reversed. This non-competitive inhibition is irreversible because the cyanide ion is tightly bound to the enzyme, making it unable to participate in the electron transport process. The inhibition is non-competitive because cyanide does not compete with the substrate (oxygen) for binding to the enzyme, but rather binds to a different site on the enzyme, preventing its function altogether.

**Why Each Wrong Option is Incorrect**
**Option A:** Non-competitive reversible inhibition is incorrect because cyanide binds irreversibly to cytochrome c oxidase, making the inhibition irreversible. Additionally, the inhibition is not reversible through changes in substrate concentration.
**Option B:** Competitive reversible inhibition is incorrect because cyanide does not compete with oxygen for binding to cytochrome c oxidase, but rather binds to a different site on the enzyme.
**Option C:** Suicide irreversible inhibition is incorrect because cyanide does not require enzymatic activation to become toxic, but rather binds directly to cytochrome c oxidase.

**Clinical Pearl / High-Yield Fact**
Cyanide poisoning is a medical emergency that requires immediate treatment. The antidote, hydroxocobalamin, binds to cyanide, forming cyanocobalamin, which is then excreted in the urine. This treatment is effective because it rapidly reverses the toxic effects of cyanide on cellular respiration.

**✓ Correct Answer: D. Non-competitive irreversible inhibition**