在双向指针p的结点前插入一个指针q的结点操作是( )。
A.
p->Prior=q;q->Next=p;p->Prior->Next=q;q->Prior=q;
B.
p->Prior=q;p->Prior->Next=q;q->Next=p;q->Prior=p->Prior;
C.
q->Next=p;q->Prior=p->Prior;p->Prior->Next=q;p->Prior=q;
D.
q->Prior=p->Prior;q->Next=q;p->Prior=q;p->Prior=q;