PLEASE ANSWER ALL PARTS! Question in Swift

9. Suppose you have declared pet to be of type Pet, but you know that in this context pet is a Dog. Complete the following statement so it forces the downcast of pet to type Dog: let dog = 10. Add code to the for loop below so it sums up only those items in various that are of type Int. var sum = 0 var various:[Any] = ["bagels", 3, 4.56, false, 5, -2] for item in various { } 11. When is it appropriate to use the as! operator? a. When you need to downcast from one type to another and you can guarantee that the type is valid. b. When you need to unwrap an optional. C. When you need to convert a value to an Any type. d. When you need to downcast from one type to another on the condition that the type is valid