Write structural formula of 2,3-dihydroxybutanal.

Explanation

To write the structural formula of 2,3-dihydroxybutanal, we will follow these steps:

### Step 1: Identify the carbon chain
Since the name is "butanal," we know that the compound contains a four-carbon chain (but-).

**Hint:** The prefix "but-" indicates that there are four carbon atoms in the main chain.

### Step 2: Determine the functional group
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