Which of the following statements is correct regarding functions fopen and open in generic C?

What happens if Xcode is not able to find a file or folder at the path defined for it in the project?

If you want to rotate an object using Core Animation, in radians, in the z axis, which of the following key paths of a layer’s CATransform3D matrix will you use?

Which VOIP protocols manages the searching of a user's call history?

Which type of queues is provided and managed by Grand Central Dispatch (GCD), using which, an app can submit tasks, in the form of block objects?

Which classes in the CallKit framework declares a programmatic interface for objects that represent a telephony action?

You are developing an application for iOS in Xcode 4.x. Which option will check if a text field with id 'TextField' is empty or not, and displaying it in a label with the id 'Output'?

Which profile is to be created to test an iOS app on a variety of devices and iOS versions?

Which option is a property of UIActivityIndicatorView object in Xcode 4.x?

As an iOS app tester, which is the advantages of having an ad hoc provisioning profile?

Which framework must be added in an Xcode 4.x project to play audio files?