Step 1: Concept
Benzene-1,2-diol consists of two hydroxyl (-OH) groups at ortho positions on a benzene ring.
Step 2: Meaning
The common name for the 1,2-isomer is Catechol.
Step 3: Analysis
- 1,3-diol is Resorcinol.
- 1,4-diol is Quinol (Hydroquinone).
Step 4: Conclusion
Hence, the correct common name is Catechol.
Final Answer: (A)