Final answer:
The HR business partner should verify the individual's name and title in the company directory and then reply to the director of finance's email requesting tax documents for an employee.
Step-by-step explanation:
The HR business partner should verify the individual's name and title in the company directory and then reply to the director of finance's email requesting tax documents for an employee. Since the business partner has never communicated with the director before, it is important to confirm their identity before sharing any sensitive information. By checking the company directory, the business partner can ensure that they are corresponding with the correct person and fulfill their department's policy of responding promptly to internal customers.