Latte’s crust of blood stain is used to detect ?

**Core Concept**
Latte's crust of blood stain is a laboratory technique used to detect the presence of hemoglobin in a sample. This method relies on the principle of hemoglobin's ability to bind with tannins, resulting in a visible crust formation. The technique is a simple and effective way to identify hemoglobin in forensic and clinical settings.

**Why the Correct Answer is Right**
The correct answer is related to the detection of hemoglobin. When a blood sample is mixed with a tannic acid solution, the hemoglobin present in the blood binds with the tannins, forming a crust-like precipitate on the surface of the liquid. This crust, also known as Latte's crust, is a visual indicator of the presence of hemoglobin. The binding of hemoglobin with tannins is a specific interaction that occurs due to the molecular structure of hemoglobin, which contains a heme group that can bind with tannins.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the correct application of Latte's crust of blood stain.
**Option B:** This option is incorrect because it does not accurately describe the detection method used in Latte's crust of blood stain.
**Option C:** This option is incorrect because it is unrelated to the detection of hemoglobin using Latte's crust of blood stain.

**Clinical Pearl / High-Yield Fact**
Latte's crust of blood stain is a simple and effective method for detecting hemoglobin in blood samples, and it is often used in forensic science to identify bloodstains at crime scenes.

**Correct Answer:** C. Hemoglobin