What are the missing reagent(s) for the reaction below? (Select all that apply? OH PBr3 A ? A C B D 1) ??? 2) NaCN SOCI2 NEt3 B TSCI NEt3 ? ? CN HCN D

What are the missing reagent(s) for the reaction below? (Select all that apply? OH PBr3 A ? A C B D 1) ??? 2) NaCN SOCI2 NEt3 B TSCI NEt3 ? ? CN HCN D