The correct answer is option 'B' - Endoplasmic reticulum.

The endoplasmic reticulum (ER) is responsible for the synthesis of lipids and the detoxification of drugs in eukaryotic cells. Let's explore this in more detail:

1. Structure of the Endoplasmic Reticulum:
- The endoplasmic reticulum is a network of membrane-bound tubes and sacs that extends throughout the cytoplasm of eukaryotic cells.
- There are two main types of endoplasmic reticulum: rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER).
- Rough endoplasmic reticulum has ribosomes attached to its surface, giving it a rough appearance under a microscope.
- Smooth endoplasmic reticulum lacks ribosomes and appears smooth.

2. Lipid Synthesis:
- The smooth endoplasmic reticulum is primarily responsible for lipid synthesis in eukaryotic cells.
- Lipids are essential components of cell membranes and play roles in energy storage, insulation, and signaling.
- The smooth endoplasmic reticulum synthesizes lipids such as phospholipids, which are the main components of cell membranes.
- It also synthesizes other lipids, including cholesterol, steroids, and triglycerides.

3. Drug Detoxification:
- The smooth endoplasmic reticulum is also involved in the detoxification of drugs and other foreign substances.
- It contains enzymes called cytochrome P450 enzymes that help metabolize and detoxify drugs, toxins, and other harmful compounds.
- These enzymes chemically modify the foreign substances, making them more water-soluble and easier for the body to eliminate.
- Drug detoxification in the smooth endoplasmic reticulum is an important process for maintaining cellular homeostasis and protecting the body from harmful substances.

In conclusion, the endoplasmic reticulum, specifically the smooth endoplasmic reticulum, is responsible for the synthesis of lipids and the detoxification of drugs in eukaryotic cells. It plays a crucial role in maintaining cellular structure and function, as well as protecting the cell from harmful substances.