William, an employee with the U$.$S$.$ Postal Service, was deployed to Afghanistan to serve in the U$.$S$.$ Army for two years. After the completion of his military duties, he resumed work at the post office. He was reemployed with an increase in pay. Which of the following laws protected William by requiring that his employer reemploy him with the seniority$,$ status, and pay rate he would have earned if he had stayed on the job during the time of his deployment?

Occupational Safety and Health Act

Americans with Disabilities Act $($ADA$)$

Vocational Rehabilitation Act

Uniformed Services Employment and Reemployment Rights Act $($USERRA$)$

Age Discrimination in Employment Act $($ADEA$)$