Cho chất sau có tên gọi là: A. 1-butyl-3-metyl-4-etylbenzen

1-butyl-3-metyl-4-etylbenzen

1-butyl-4-etyl-3-metylbenzen

1-etyl-2-metyl-4-butylbenzen

4-butyl-1-etyl-2-metylbenzen.