Amino acid are

Options

A. Acidic
B. Basic
C. Amphoteric
D. All of these

Explanation

### Step-by-Step Solution:

1. **Definition of Amino Acids**:
Amino acids are organic compounds that serve as the building blocks of proteins. They contain both an amino group (-NH2) and a carboxyl group (-COOH).

2. **Understanding Properties**:
Amino acids exhibit different properties based on their functional groups. The carboxyl group can donate a proton (H+), making it acidic, while the amino group can accept a proton, making it basic.

3. **Amphoteric Nature**:
The term "amphoteric" refers to a substance that can act as both an acid and a base. Since amino acids can donate protons (due to the carboxyl group) and accept protons (due to the amino group), they are classified as amphoteric.

4. **Conclusion**:
Therefore, amino acids are considered amphoteric because they possess both acidic and basic properties. This means they can react with both acids and bases to form salts.

5. **Final Answer**:
The correct classification of amino acids is that they are amphoteric.