Amino Acids: Structure, Properties, and Functions

Which of the following statements is/are correct about amino acids?

1. Alanine, valine, leucine, and isoleucine have aromatic hydrocarbon side chains.
2. Methionine has a thiol ether side chain that resembles an n-butyl group in many of its physical properties.
3. Proline has conformational constraints imposed by the cyclic nature of its pyrrolidine side chain.