Justify the following statement with the help of a suitable example: “In a class hierarchy of several levels of several levels, if we want a function at any level to be called through a base class...

Justify the following statement with the help of a suitable example:
“In a class hierarchy of several levels of several levels, if we want a function at
any level to be called through a base class pointer then the function must be
declared as virtual in the base class”.