Transparent, because transparent means that you are allowing light to pass through, and you do not want a background color.
Eric Hosking was the first.
Answer:
some people may select war and terrorism for the utilitarianism.
others follow peace and love against war.
but what we select according to utilitarianism won't be always positive.
some decisions would end up as disaster.
we should choose the decision which is better for the society.