Spectroscopy

Step 1: Identify chemically equivalent proton groups.
The structure contains: 1. A methoxy group (OCH ) → 3 equivalent protons → singlet.
2. An aldehyde proton (CHO) → isolated → singlet.
3. One OH proton → exchangeable → appears as a singlet.
Step 2: Check aromatic protons.
Due to substitution pattern, aromatic ring protons are not equivalent, so they will not give singlets and are ignored for this question.
Step 3: Conclusion.
Total singlets observed = 3.