One problem with utilitarianism is that it requires someone or some entity that is trusted to make decisions for society that produces the greater good. This is a problem because...
a) different people have different preference for what is considered the greater good.
b) it is impossible to get people to agree on who could be trusted to carry out this responsibility.
c) it may require people to give up what makes their lives happy, i.e what makes their lives worth living.
d) all of the above.