"Compassion and tolerance are not a sign of weakness, but a sign of strength." Dalai Lama
a) I think it means that if you can be compassionate and tolerate people, that you have to be strong enough to do that.
b) I could try to be more compassionate to people, and also try to tolerate them instead of losing my temper.
c) I believe that it could. If people had more compassion for people and tolerated them more, then it would be more peaceful. There wouldn't be as much fights.
d) It would make the world more peaceful. There would be less wars.