which of the following is aromatic AA?

Options

A. tyrosine
B. tryptophan
C. phenyl alanine
D. al the above

Answer

To determine which of the given amino acids are aromatic, we need to understand what aromatic amino acids are. Aromatic amino acids are those that contain an aromatic ring, specifically a benzene ring, in their side chains.

### Step-by-Step Solution:

1. **Identify the Amino Acids**: The options provided are:
- Tyrosine
- Tryptophan
- Phenylalanine
- All of the above

2. **Define Aromatic Amino Acids**: Aromatic amino acids are characterized by the presence of an aromatic ring in their structure. This typically refers to a benzene ring.

3. **Analyze Each Option**:
- **Tyrosine**: Contains a phenolic hydroxyl group attached to a benzene ring, making it aromatic.
- **Tryptophan**: Contains an indole ring, which is also aromatic.
- **Phenylalanine**: Contains a simple benzene ring in its side chain, making it aromatic as well.

4. **Conclusion**: Since all three amino acids (tyrosine, tryptophan, and phenylalanine) contain an aromatic ring, they are all classified as aromatic amino acids.

5. **Final Answer**: The correct option is **All of the above**.