**Core Concept**
The Golgi apparatus is a complex organelle found in eukaryotic cells responsible for processing and modifying proteins and lipids synthesized by the endoplasmic reticulum. It plays a crucial role in protein glycosylation, sorting, and packaging for secretion or intracellular transport.

**Why the Correct Answer is Right**
The correct answer involves the modification of proteins and lipids by adding carbohydrate molecules (glycosylation) and other types of post-translational modifications. The Golgi apparatus contains enzymes that catalyze these reactions, allowing for the creation of complex glycoproteins and glycolipids. This process is essential for cell-cell communication, cell signaling, and the formation of cellular structures such as the extracellular matrix.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the Golgi apparatus is not primarily involved in protein degradation or recycling. While it can modify proteins, it is not responsible for breaking them down.
* **Option B:** This option is incorrect because the endoplasmic reticulum (ER) is the organelle responsible for protein synthesis and folding, not the Golgi apparatus. The ER is the site where proteins are initially synthesized and modified before being transported to the Golgi apparatus.
* **Option D:** This option is incorrect because the lysosome is an organelle involved in cellular digestion and recycling, not protein modification and sorting. While both the Golgi apparatus and lysosome are involved in cellular processing, they have distinct functions.

**Clinical Pearl / High-Yield Fact**
The Golgi apparatus is named after the Italian scientist Camillo Golgi, who first discovered this organelle in the late 19th century. The Golgi apparatus is a complex organelle composed of multiple flattened sacs and tubules, often referred to as cisternae and vesicles.

**Correct Answer: C. Protein modification and sorting.**