“380V/220V Y/△” noted on the nameplate of a non-synchronous motor means that（）

A. the armature terminals of the motor should be connected in star formation when voltage of power supply is 380
B. the armature terminals of the motor should be connected in star formation when voltage of power supply is 220
C. both A and B are correct
D. the armature terminals of the motor should be connected in reverse ways of A and B