Which of the following keyword is used to overload user-defined types by defining static member functions?

public sample operator + ( sample a, sample b )

public abstract operator + ( sample a, sample b)

public abstract sample operator + (sample a, sample b )

public static sample operator + ( sample a, sample b )

1. The overridden base method must be virtual, abstract or override.
2. Both the override method and the virtual method must have the same access level modifier.
3. An override declaration can change the accessibility of the virtual method.
4. An abstract inherited property cannot be overridden in a derived class.
5. An abstract method is implicitly a virtual method.

1. Methods
2. Properties
3. Events
4. Fields
5. Static fields

1. It is a keyed collection.
2. It is a ordered collection.
3. It is an indexed collection.
4. It implements a IDictionaryEnumerator interface in its inner class.
5. The key - value pairs present in a HashTable can be accessed using the Keys and Values properties of the inner class that implements the IDictionaryEnumerator interface.

Stack st = new Stack();
st.Push("hello");
st.Push(8.2);
st.Push(5);
st.Push('b');
st.Push(true);