I'd like to start my  own business-that's _____ I'd do if I  had the money.  [ ]

A. why                    

B. when    

C. which                

D. what

负载为三角形连接时，对称三相电源电压380V，每相阻抗为Z=（8-6j）Ω，求负载的相电压，相电流，线电流。