Okay, let's tackle this question about hemoglobin. The user provided a question asking for a true statement about hemoglobin with options A to D but no specific options listed. They also mentioned the correct answer is missing. Hmm, maybe the options were accidentally omitted. Since I need to create a detailed explanation, I should first assume possible correct and incorrect options based on common hemoglobin-related facts.

Hemoglobin is a key topic in physiology and pathology. Common true statements might include its structure, function, oxygen binding, or related conditions like sickle cell anemia. Let's think of typical distractors. For example, correct answers might involve the alpha and beta subunits, heme groups, or the Bohr effect. Incorrect options could be about the number of subunits, iron content, or oxygen affinity.

Wait, the correct answer needs to be identified. Let's say the correct option is something like "Hemoglobin is a tetramer composed of two alpha and two beta chains in adults." Then the incorrect options could be things like "Hemoglobin has four heme groups each with iron," which is actually true, but maybe the distractor is phrased incorrectly. Alternatively, maybe an option about myoglobin instead of hemoglobin.

But without the actual options, I have to make educated guesses. Let's proceed by outlining a core concept about hemoglobin. The core concept is that hemoglobin is a tetrameric protein in red blood cells that transports oxygen. It consists of four subunits, each with a heme group that binds oxygen.

The correct answer would then detail the structure, like the alpha and beta subunits. For example, adult hemoglobin (HbA) is α2β2. Then the incorrect options might mention gamma chains (fetal hemoglobin), or incorrect numbers of heme groups. Another common mistake is confusing myoglobin's structure with hemoglobin's.

Clinical pearls might include the Bohr effect, where lower pH reduces oxygen affinity, or the difference between adult and fetal hemoglobin in oxygen binding. High-yield facts could be the heme's iron in the ferrous state, or the cooperative binding of oxygen.

Wait, but the user's example might have a specific correct answer in mind. Let's structure this as if the correct answer is about the structure. So, the core concept is hemoglobin's quaternary structure. Then explain why that's correct, and why other options (like myoglobin being monomeric, or incorrect subunit counts) are wrong.

I need to make sure each section is concise, uses correct terminology, and addresses the possible distractors. Also, the clinical pearl should highlight a key point, like the Bohr effect or the role of 2,3-BPG. Let's put it all together in the required sections, making sure to follow the formatting rules.

**Core Concept**
Hemoglobin is a tetrameric protein in erythrocytes responsible for oxygen transport. It consists of two alpha (α) and two beta (β) globin chains in adults (HbA), each binding one heme group with iron (Fe²⁺) for oxygen binding.

**Why the Correct Answer is Right**
The correct statement (e.g., "Hemoglobin is a tetramer composed of two α and two β chains") reflects its quaternary structure. Each subunit contains a heme group, allowing cooperative oxygen

✓ Correct Answer: A. Each hemoglobin molecule is made of 4 polypeptides of each subunit