Gene is a 24-year-old stock clerk at a large supermarket. He recently broke his arm in a cycling accident. Because of his broken arm, Gene is struggling to perform his duties. He asks his manager, Jake, if he could temporarily work on a different job till his arm heals. However, Jake overlooks Gene's request, and Gene is forced to perform his usual duties. After this incident, Jake now tries to avoid Gene in the workplace whenever possible. In the given scenario, which of the following types of discrimination is Gene facing?
A) Age discrimination.
B) Sex discrimination.
C) Racial discrimination.
D) Disability discrimination.