Chỉ ra đâu là amin bậc I

1.     Chỉ ra đâu là amin bậc I ?

A.  CH3CH2CH2CH2NH-C6H5.          B. CH3 – N – CH3

                                                         ï

                  CH3                                                                                                        CH3

      ï

C. CH3 – C – CH3.                                                                                     D.   CH3-NH-CH2-CH3.

      ï

                  NH2