A.virtual class B{}; virtual class A : public B {};
B.virtual class B{}; class A : virtual public B {};
C.class B{}; class A : virtual public B {};
D.virtual class B{}; class A : public B {};
A.ti:(virtual)orti:(digital)andti:(service)
B.ti:(virtual)andti:(digital)andti:(service)
C.ti:(virtual)andti:(service)orti:(digital)
A.Visual Private Network
B.Virtual Private Network
C.Virtual Public Network
D.Visual Public Network
A、is nothing
B、is something
C、can be exchanged with virtual money
D、can make anything possible