**Core Concept**
The visibility of tattoos after death depends on the preservation of the skin and the presence of melanin, the pigment responsible for tattoo ink visibility. Tattoos appear more prominent when the skin is well-preserved and melanin is present.

**Why the Correct Answer is Right**
The presence of tattoo ink can be confirmed by histopathological examination of the skin, specifically through the use of a special stain called Prussian blue. This stain reacts with the iron oxide particles in the tattoo ink, allowing for its visualization under a microscope. This method is particularly useful when the tattoo is not visible macroscopically due to skin degradation or other factors.

**Why Each Wrong Option is Incorrect**
**Option A:** Blood tests for tattoo ink are not a reliable method for confirming the presence of a tattoo, as tattoo ink is not systemically absorbed and therefore not detectable in the bloodstream.
**Option B:** X-rays may not be able to visualize tattoo ink, which is composed of non-radioopaque materials.
**Option C:** Skin scrapings may not be sufficient for confirming the presence of tattoo ink, as the ink is dispersed throughout the dermal layer and may not be present in sufficient quantities in a skin scraping.

**Clinical Pearl / High-Yield Fact**
In cases where the tattoo is not visible, it is essential to consider histopathological examination as a means of confirming its presence, particularly in situations where family members or witnesses claim the individual had a tattoo.

**Correct Answer:** C.