Erythrocytes are enucleated. They will have no nucleus in them, hence no DNA. Serum is blood plasma without clotting factor. Platelets are like RBCs, i.e. They do not have nucleus. Therefore, answer is Leucocytes, or WBCs. They have nucleus, and hence contains DNA. Thus, DNA PROFILING can be done on (b)LEUCOCYTES

Choosing the Ideal Component for DNA Profiling

To identify the criminal using DNA profiling techniques, it is crucial to select the most suitable blood component that contains genetic material for analysis. Here are the options and an explanation of each:

Erythrocytes
Erythrocytes, or red blood cells, do not contain a nucleus and therefore do not possess DNA. As a result, they are not ideal for DNA profiling as they lack the genetic material necessary for identification.

Leukocytes
Leukocytes, or white blood cells, are the primary cells used for DNA profiling. They contain a nucleus with DNA that can be extracted and analyzed for genetic information. Leukocytes are commonly found at crime scenes in blood stains and are the preferred choice for identifying the criminal through DNA analysis.

Platelets
Platelets are cell fragments involved in blood clotting and do not contain a nucleus or DNA. Therefore, they are not suitable for DNA profiling and cannot be used to identify the criminal based on genetic information.

Serum
Serum is the liquid component of blood that remains after clotting and does not contain cells or DNA. As a result, serum is not ideal for DNA profiling as it lacks the genetic material necessary for identification.

In conclusion, when using DNA profiling techniques to identify the criminal based on blood stains found at a murder scene, leukocytes are the most suitable blood component to analyze. They contain DNA within their nuclei, allowing for accurate genetic profiling and comparison for forensic purposes.