Okay, let's start by understanding the user's query. They provided a multiple-choice question about chromatography, specifically asking which compound is negatively charged. The correct answer is given as option C, but the options themselves are missing labels. The user wants a detailed explanation following specific formatting rules.

First, I need to recall the core concept of chromatography. Chromatography separates compounds based on their interaction with the stationary and mobile phases. In ion-exchange chromatography, charged compounds bind to oppositely charged resins. The question is about a negatively charged compound, so the stationary phase would be positively charged, like a cation exchange resin.

The correct answer is option C. I need to explain why. For a compound to bind to a positively charged resin, it must be negatively charged. Common anions include proteins, nucleic acids, or organic acids. The explanation should mention the charge interaction and how this affects separation.

Now, the wrong options. Options A, B, and D would be incorrect if they are neutral or positively charged. For example, a neutral compound wouldn't bind, and a positively charged one would bind to an anion exchange resin instead. Need to clarify why each is wrong concisely.

The clinical pearl here is recognizing that in ion-exchange chromatography, the charge of the compound determines the resin used. Remembering that cation exchangers bind anions and vice versa is key. Also, mention common examples like DEAE (anion exchanger) and CM (cation exchanger) as mnemonics.

Finally, structure the answer into the required sections: Core Concept, Why Correct, Why Wrong, Clinical Pearl, and Correct Answer. Keep each section concise, use bold for key terms, and ensure the total character count is under 2,500. Avoid markdown headings beyond the specified ones. Make sure the explanation is clear for a postgraduate medical student preparing for exams like NEET PG or USMLE.

**Core Concept**
Ion-exchange chromatography separates charged molecules based on their interaction with oppositely charged resins. Negatively charged compounds (anions) bind to cationic resins (e.g., DEAE-cellulose), while positively charged compounds (cations) bind to anionic resins (e.g., CM-cellulose).

**Why the Correct Answer is Right**
The correct answer (C) represents a negatively charged compound, such as a deprotonated carboxylic acid or phosphorylated molecule. These anions bind to positively charged cation-exchange resins, allowing retention during chromatography. The charge interaction determines elution order, with stronger binding (higher charge density) delaying release.

**Why Each Wrong Option is Incorrect**
**Option A:** Likely neutral or hydrophobic (e.g., steroid), which does not interact with ion-exchange resins.
**Option B:** Positively charged (e.g., protonated amino group), which binds to anion-exchange resins, not cationic ones.
**Option D:** Neutral zwitterionic compound (e.g., amino acid at isoelectric point), which neither binds nor elutes significantly.

**Clinical Pearl / High-Yield Fact**
Remember: **“Cation exchanger binds anions, anion exchanger binds cations.”** For chromatography, the resin’s charge dictates the target compound’s charge.

✓ Correct Answer: B. CMC (carboxy methyl cellulose)