Answer
A utilitarian would allow as much income inequality to maximize the total utility of the society. In other words, a utilitarian would allow for a minimal amount of income inequality since utilitarians would aim for a more equal distribution of income. (However, this would only be partially obtained since the utilitarian would realize the redistribution of income hurts incentives.)
Work Step by Step
A liberal would focus on the person who is the worst off in the society and try to equalize incomes so that the worst off person has a 'just' income.
A libertarian would not focus on the redistribution of income as long as the ability (or process) of getting an income is fair.
