Swift Question

1) Assume that A is a superclass of B. Choose all the following declarations that are legal.

A) var a: A = A()

B) var a: A = B()

C) var b: B = A()

D) var b: B = B()

2) Assume that A is s superclass of B. Variable obj is declared to be of type A. Which of the following is the correct syntax to downcast obj to type B and call a method m defined in B but not in A.

A) obj.m()

B) (obj as! B).m()

C) (obj as? B).m()

D) B(obj).m()

F) None of the above