please help with these swift questions

I will thumbs up in rating !!!

1. what is an IBOutlet

A) It is a variable in a view controller that references a user interface element in Interface Builder. B)It is a method in a view controller that gets executed when a user interacts with a a user interface element in Interface Builder. C)It is the memory location of a Storyboard in Interface Builder.

2. When a Double is initialized with a String a failable initializer is called. What type is value in the following line of Swift code?

var value = Double("51.38")

A) Double B) Double! C) Double? D) String E) String? F) Void

3. Given the following OuterPlanets enumeration: enum OuterPlanets: String { case mars, jupiter, saturn, uranus, neptune } What is the rawValue for jupiter?

A) 1 B) 2 C) 5 D) j E) "jupiter" F) .jupiter

4. Given:

struct Circle { var x = 0.0, y = 0.0, width = 0.0 } var circle = Circle()

Which of the following is used to set the width property of circle to 10.0 in Swift?

A) circle["width"] = 10.0 B) circle.setWidth(10.0) C) circle.width = 10.0 D) circle->width = 10.0

5. Given: struct Font { var name: String var size: Double } Which of the following is the correct line of Swift code for creating an instance of a Font with a name of "times" and a size of 12.0?

A) let font = new Font(name: "times", size: 12.0) B) let font = Font(name: "times", size: 12.0) C) let font = Font("times", 12.0) D) let font = new Font("times", 12.0)