-种核酸外切酶与pApGpUpCpApG -pU -起保温，其水解产物中不含有

A．PA +pG +pUpCpApGpU

B．PApG +pUpC +pApGpU

C．2pA +2pG +2pU +pC

D．PApGpUpCpA +pG +pU

E．PApGpUpCpApG +pU