The newborn was 34 weeks' gestation. The birth weight is 2800g. the fetal heart is slow, the fetal movement is reduced, Ihe whole body color is blue at the time of birth.The tension of the four limbs is low. The breathing is weak, and the amniotic fluid is II degree. In the resuscitation of asphyxia, which of the following circumstances requires endotracheal intubation(气管插管) in the child during resuscitation A. respiratory secretions（分泌物）increase B. breathing irregularly. C. heart rate is 80 beats / min after resuscitation D. when after birth 5 minutes, Apgar score was 8 E. mask positive pressure oxygen supply invalid(无效)