Polymorphism: 
   It is also k.a., Dynamic Method dispatch
   
   Poly = Multiple, more than one, many
   morphism= Behaviour
   
Def: "Polymorphism is the ability of an object to take on many forms". 
     The most common use of polymorphism in OOP occurs when a parent class reference is used to refer to a child class object.


Types of polymorphism:

(a) Compile Time OR static polymorphism
   Ex: Method overloading
   Bcoz here based on the input, we can decide which method will get execute during the compile time.
   
(b) Dynamic OR runtime polymorphism
   Ex: Method Overriding
   Bcoz here compiler will decide during runtime which method to execute.