What does the following C# code set defines?

public Gen(T o) 
{
     ob = o; 
}

A. -= B. += C. /= D. *=

A. Removes a delegate from the current delegate B. Adds a new delegate to the current delegate C. Invokes all the delegates bound to the current delegate D. Retrieves an array of delegates bound to the current delegate

A. A function that is called when an event is raised B. A function that is called to subscribe to an event C. A function that is called to unsubscribe from an event D. A function that is called to handle an event

A. Func B. Predicate C. Action D. EventHandler