The app is in the background but not executing code. What State App is it in?

Which 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 CodeDate classes maintains a small connection pool for allowing concurrent database operations for NSSOLiteStoreType persistent stores?

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?