单项选择题
Given: What is the result?()
A.harrier B.shepherd C.retriever D.Compilation fails. E.retriever harrier F.An exception is thrown at runtime.
A.a B.b C.c D.ac E.abc
A.Alpha a = x; B.Foo f = (Delta)x; C.Foo f = (Alpha)x; D.Beta b = (Beta)(Alpha)x;