The correct option is D Asperger syndrome - Signboard
Hand signs are used to communicate with a deaf person. Each alphabet has a corresponding hand sign.
Wheelchairs are useful for people with walking disability.
Braille system is a code of raised dots on paper. It helps visually impaired people to read.
People with Asperger syndrome need to overcome stress related to bright light and change, so signboards are not helpful in this case.