Select the principal group when the following groups are present in a molecule.
`-Br ,-NH_2 ,-Cl ,-OH`

Explanation

To determine the principal functional group among the given groups (-Br, -NH2, -Cl, -OH), we will follow a systematic approach based on the priority order of functional groups in organic chemistry.

### Step-by-Step Solution:

1. **Identify the Functional Groups**: The groups present in the molecule are:
- -Br (bromo)
- -NH2 (amino)
- -Cl (chloro)
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