Which of the following is a common body location where DNA can be easily obtained?

Blood is a common body location where DNA can be easily obtained due to its high cellular concentration of nucleated cells. Blood contains white blood cells, which hold DNA and can be isolated effectively through various laboratory techniques. Since blood is often present at crime scenes and can be collected with relative ease, it serves as a vital source for DNA analysis in forensic investigations.

While bone can indeed provide DNA, particularly in cases where other samples are not available, obtaining DNA from bone is generally more complex due to the need for specific extraction methods, especially if the bone is degraded. Dandruff might contain skin cells from which DNA could be extracted, but it's not as reliable or abundant as blood.

Considering these aspects, blood stands out as the most common and practical source for DNA in a forensic context. It is frequently used in crime scene investigations for identification purposes due to its accessibility and the ease of its collection.