The following reaction is known as `:`
Carbonyl compound `underset(50%"NaOH solution")overset(HCHO)rarr PhCH_(2)OH+HCOONa`

Options

A. Aldol condensation reaction
B. Cannizzaro reaction
C. Perkin's reaction
D. Claisen condensation reaction

Explanation

To solve the question regarding the reaction involving a carbonyl compound, we can break it down step by step.

### Step-by-Step Solution:

1. **Identify the Reactants**: The reaction involves a carbonyl compound (PhCHO, which is benzaldehyde) and formaldehyde (HCHO) in the presence of a 50% NaOH solution.

2. **Write the Reaction**: The reaction can be represented as:
\[ \text{PhCHO} + \text{HCHO} \xrightarrow{\text{50% NaOH}} \text{PhCH}_2\text{OH} + \text{HCOONa} \]
Here, PhCH2OH is benzyl alcohol and HCOONa is sodium formate.

3. **Determine the Type of Reaction**: This reaction is a type of condensation reaction where two carbonyl compounds react in the presence of a base to form an alcohol and a salt.

4. **Name the Reaction**: The specific reaction taking place here is known as the **Caine-Giarro reaction**. This name is derived from the chemists who studied this reaction.

5. **Select the Correct Option**: Based on the information provided, we conclude that the reaction is known as the Caine-Giarro reaction. If options are provided, we would select the one that states this name.

### Final Answer:
The reaction is known as the **Caine-Giarro reaction**.

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