单项选择题

如果母联为分相断路器,各相的常开、常闭接点应()接入BP-2B母差保护

A.常开接点串联,常闭接点并联
B.常开、常闭接点都串联
C.常开接点并联、常闭接点串联
D.常开、常闭都并联