Which of these could be an appropriate protocol declaration in Swift?

In context of a Swift subscript, which of the following is correct?

What is used to import Objective-C files into Swift?

What keyword is used to indicate a custom operator that will appear in between two targets, similar to the addition operator in this example? var sum = 10 + 10

Which is correct regarding Swift enumeration members when they are defined?

What type of object are Swift Structures?

Can cyclical relationships exist in value types?

A closure is a function without a name.

var varB = 3.14159ng is the c, varB is inferred to be of type _____

print(myStr) What will be the output of the above code snippet?

var myVar = 100 myVar = 'Hello World' print(varA) The output will be