Which of the following is a correct definition for an instance method, print_age(), that has two parameters, date_of_birth and date_today, passed to it?

The definition provided as the correct answer appropriately includes the necessary parameters and follows the conventions for defining an instance method in Python. An instance method in a class must include self as the first parameter, which refers to the instance of the class itself. This allows the method to access attributes and other methods associated with that instance.

In this case, print_age(self, date_of_birth, date_today) correctly identifies self as the first parameter followed by the two additional parameters, date_of_birth and date_today. This structure allows the method to properly interact with the instance while accepting specific input parameters needed for its functionality.

The other definitions do not conform to the requirements for an instance method. They lack the necessary self parameter, which is critical for any method that is intended to operate within the context of an instance of a class in Python. Without self, the method would not have access to the instance's attributes or other methods, rendering it ineffective as an instance method.