people with mental－health problems want most of all is a more equal and open working culture.
A. That
B. What
C. When
D. All what
网友回答
A. That
(答案→)B. What
C. When
D. All what
解析：主语从句 people with mental-health problem want缺少宾语，要用what引导，且充当want的宾语。故选B。