A web application developer is writing code for validating the user input. His aim is to verify the user input against a list of predefined negative inputs to ensure that the user does not submit…

A web application developer is writing code for validating the user input. His aim is to verify the user input against a list of predefined negative inputs to ensure that the user does not submit any malicious or invalid input. Which of the following mechanisms can he implement to identify the input filtering mechanism being implemented by the developer?