Final answer:
Option (D), Form I-9 has a two-year retention period, as stipulated by the Immigration Reform and Control Act of 1986, ensuring that employees' eligibility to work in the United States is on record.
Step-by-step explanation:
The document that has a two-year retention period is Form I-9. According to the regulations set forth by the Immigration Reform and Control Act of 1986, employers must retain completed Form I-9 for all employees for two years after the date of hire or for one year after employment is terminated, whichever is longer.
This form is used to verify the identity of employees and to ensure that they are eligible to work in the United States. Other documents such as work time schedules or hospital workers' agreements to an 8/80 plan may have different retention periods based on industry regulations or company policies.