Employers must return an age certificate to an employee by when?

The correct timeline for an employer to return an age certificate to an employee is when requested by the employee. This means that when an employee provides a request for their age certificate, the employer is expected to respond and provide the necessary documentation in a timely manner. This approach ensures that employees can access the information they need without unnecessary delays, facilitating smoother processes related to employment verification, especially in jobs where age verification is critical, such as in industries that have minimum age requirements or restrictions.

Understanding the context of other options clarifies the importance of the correct answer. Returning it by the end of the week or month might imply a specific time frame that may not address the immediate nature of an employee's request. Additionally, offering an age certificate by the end of a term doesn’t match the immediate actions required when an employee necessitates this documentation. Thus, the correct answer emphasizes the requirement for the employer to act promptly in compliance with the employee's request, which is fundamental in payroll and human resources practices.