To solve the question regarding the parts of filament, hook, and basal body, we need to analyze the options provided and understand the structure of flagella in different organisms.
### Step-by-Step Solution:
1. **Understanding Flagella**:
- Flagella are structures that aid in locomotion for both prokaryotic and eukaryotic organisms. They allow organisms to move by whipping or rotating.
2. **Identifying the Components**:
- The question specifies three components: filament, hook, and basal body.
- The filament is the long, whip-like structure that extends outside the cell.
- The hook is the curved structure that connects the filament to the basal body.
- The basal body is the part embedded in the cell membrane and acts as an anchor for the flagellum.
3. **Comparing Prokaryotic and Eukaryotic Flagella**:
- In prokaryotes (like bacteria), the flagella are composed of these three parts (filament, hook, and basal body) and are made of a protein called flagellin.
- In eukaryotes, the flagella have a different structure and are made of microtubules arranged in a "9+2" formation. They do not have a hook and basal body in the same sense as prokaryotic flagella.
4. **Analyzing the Options**:
- Option (a) Flagella in prokaryotes: This option includes filament, hook, and basal body.
- Option (b) Flagella in eukaryotes: This option does not include all three components as described.
- Option (c) Fimbriae: This is incorrect as fimbriae are different structures used for attachment, not locomotion.
- Option (d) Flagella in both eukaryotes and prokaryotes: While flagella exist in both, the specific components mentioned (filament, hook, and basal body) are characteristic of prokaryotic flagella.
5. **Conclusion**:
- The correct answer is (a) Flagella in prokaryotes, as filament, hook, and basal body are indeed the parts of the flagella found in prokaryotic organisms.
### Final Answer:
(a) Flagella in prokaryotes
