Which of the following is used in Friedel-Craft acylation reaction

Explanation

To determine which compound is used in the Friedel-Crafts acylation reaction, we need to understand the components and conditions required for this reaction.

### Step-by-Step Solution:

1. **Understanding Friedel-Crafts Acylation**:
Friedel-Crafts acylation is a reaction that introduces an acyl group (RCO-) into an aromatic ring. It is a type of electrophilic aromatic substitution.

2. **Reagents Required**:
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