Which type of validation we must implement the Validateable interface (or extend ActionSupport class) and provide the implementation of validate method?

Which type of validation we must implement the Validateable i

1.	Which type of validation we must implement the Validateable interface (or extend ActionSupport class) and provide the implementation of validate method?
A.	By Input Validation
B.	By Ajax Validation
C.	By Custom Validation
D.	None of the above
Answer» D. None of the above