Which of the following is true?

What is the effect of using 'weak' in the following @property definition: @property (nonatomic, weak) SomeClass *responder; ?

Which scenario will not result in NSOperation throwing an exceptions:

In Objective C, all instance methods are accessors.

What class can implement Document Objects?

Which method is used to deallocate all the noncritical custom data structure associated with your view controller?

Which event of the Apple Pay JS framework defines the attributes contained by the onshippingmethodselected callback function?

Which is an object that manages a memory—based data buffer in Grand Central Dispatch (GCD)?

Which classes manages notif‌ication-related activities for an app or app extension?

Which ApplePay JS Data Types showcases the outcome of authorizing a payment request and contains encrypted payment information?

Which Messages framework classes is used to display a dynamically-generated list of stickers. which is capable of drag-and-drop functionality?