Final answer:
The cell wall is the only component listed that can be found outside of a cell's membrane. Cytoplasm, nucleus, and ribosomes are all located within the cell membrane.
Step-by-step explanation:
The components that can be found outside of a cell's membrane include the cell wall (D). The cytoplasm (A), which includes ribosomes, is found within the cell membrane, encapsulating all the internal components of the cell, excluding the nucleus. The nucleus (B) is also located within the cell, surrounded by its own membrane. Ribosomes (C) can be found both bound to the endoplasmic reticulum within eukaryotic cells, and freely floating in the cytoplasm, but not outside the cell membrane. In contrast, a cell wall is an additional layer found outside the cell membrane in various organisms such as plants, bacteria, fungi, and some protists. However, not all cells have a cell wall; for example, animal cells do not. Therefore, the correct answer to which components can be found outside a cell's membrane is the cell wall (D).