Mill Justified Utilitarianism from Rival Perspectives When He Argued

Mill justified utilitarianism from rival perspectives when he argued

A) that without utilitarianism to provide a determinate standard of justice,one is always left with a plethora of competing principles of justice,all of which seem to have plausibility but are mutually incompatible.
B) that social utility is irrelevant to issues of justice.
C) against worker participation.
D) that only utilitarianism itself,as a normative theory,can provide an answer to the question: What economic system will bring more good to society than any other system?