## **Core Concept**
The question tests the knowledge of cell biology, specifically about organelles that contain DNA. In eukaryotic cells, DNA is primarily found in the nucleus, but there are organelles outside the nucleus that also contain DNA.

## **Why the Correct Answer is Right**
Mitochondria are known to have their own DNA, often referred to as mtDNA. This DNA is separate from the DNA found in the nucleus and encodes for some of the proteins involved in mitochondrial function, particularly those involved in oxidative phosphorylation. Mitochondrial DNA is circular in shape, similar to bacterial DNA, and is inherited solely from one's mother.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Endoplasmic reticulum (ER) does not contain DNA; it is involved in protein synthesis, folding, and transport, as well as lipid synthesis.
- **Option B:** Lysosomes are membrane-bound vesicles containing digestive enzymes and do not have DNA; they are responsible for cellular digestion and recycling of macromolecules.
- **Option C:** Golgi apparatus is involved in protein modification, sorting, and packaging but does not contain DNA.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that mitochondrial DNA mutations can lead to a variety of diseases, often affecting high-energy-demanding tissues like muscle and nerve cells. These diseases are inherited maternally.

## **Correct Answer:** C. Mitochondria.