Which of the following is (are) our best hope for reducing the stigma against those diagnosed with a psychological disorder?
increase contact, increase education, increase equality legislation

As the questions states "are," this implies that multiple answers are possible. In that case, all of these would be useful strategies to reduce the stigma against people with psychological disorders.

If people increased their contact with members of this population, they would stop seeing psychological disorders as something far from them and difficult to understand. Moreover, if they increased their education on the subject, they would be less likely to have prejudices or stigma against these people. Finally, increased equality education would allow members of this population to be more included in society, which would most likely decrease the stigma.