The correct answer to the question is:
b. organelles
Explanation:
1. In eukaryotic cells, membrane-bound structures are known as organelles.
2. Organelles perform specific functions within the cell, such as the nucleus which houses the genetic material, the mitochondria which produce energy, and the endoplasmic reticulum which is involved in protein synthesis.
3. Cell walls are found in plant cells but are not membrane-bound structures in eukaryotic cells.
4. Cytoplasm is the gel-like substance inside the cell where organelles are suspended but is not the term used for membrane-bound structures.
5. Prokaryotes, such as bacteria, lack membrane-bound organelles like those found in eukaryotic cells.
