Final answer:
The Americans with Disabilities Act (ADA) mandates nondiscrimination in public places, sets standards for the width of doorways and hallways, and requires the accessible placement of door handles, grab bars, and handrails; encompassing all of the above provisions.
Step-by-step explanation:
The Americans with Disabilities Act (ADA) mandates a comprehensive range of provisions to ensure equality for people with disabilities. These include 1) nondiscrimination in public places, which encompasses equal opportunities in employment, the use of accommodations and access to public services. Also included are 2) standards for the width of doorways and hallways, and 3) accessible placement of door handles, grab bars, and handrails, which facilitate easier navigation and usability for individuals with various disabilities. Therefore, the correct answer to what the ADA mandates for people with disabilities is 4) all of the above.