Name the smallest aldose which forms cyclic hemiacetal and the functional groups are involved in its formation.

Explanation

To solve the question, we need to identify the smallest aldose that can form a cyclic hemiacetal and determine the functional groups involved in its formation.

### Step-by-Step Solution:

1. **Identify the Smallest Aldose:**
- An aldose is a type of sugar (monosaccharide) that contains an aldehyde group. The smallest aldose is **D-glyceraldehyde**, which has three carbon atoms (C3H6O3).

2. **Understanding Cyclic Hemiacetal Formation:**
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