Which of the following is NOT a root class in the context of Objective-C?

Question

Which of the following is NOT a root class in the context of Objective-C?

a. NSObject

b. NSNetworkService

c. NSBase

d. NSProxy

(its a single select question)

I get this question in a online exam for iOS 6. I knowNSObject and NSProxy are root classes. But I am not aware of any class with name NSNetworkService or NSBase.

I am wondering what is the correct answer for this question.

Note: I have cleared that test and not posting this question for cheating.

Answer 1

I'm not aware of the classes NSNetworkService and NSBase (of course someone could name his class with prefix NS). NSObject and NSProxy are base classes, though. So the correct answer is b and c.

Edit (thanks Abizern): In the context of iOS, only NSObject is available which would add answer d to the set of classes NOT being a root class. I guess the opposite question "Which of the following classes are root classes?" would have been easier to answer given the fact that you said you can choose only one option ;)