hardC++multiple and virtual inheritance layoutSingle-choice MCQ

struct A {char a; virtual void f();}; struct B {char b; virtual void g();}; struct C : A, B {char c;}; on x86-64 Itanium ABI (8-byte vptr/alignment). What is sizeof(C) and how many vptrs does a C object hold?

struct A { char a; virtual void f(); }; struct B { char b; virtual void g(); }; struct C : A, B { char c; }; // sizeof(C)? number of vptrs?