In What Sense Is Act Utilitarianism Sometimes Thought to Be

In what sense is act utilitarianism sometimes thought to be too demanding?

A) Because it requires you to maximize overall happiness, act utilitarianism sometimes allows you to do things that most people regard as morally wrong.
B) Because it requires you to make as many people happy as possible, act utilitarianism sometimes requires you to make other people happy at your own expense.
C) Because it requires you to count everyone's happiness as equal to your own and that of your loved ones, act utilitarianism sometimes requires you to make great sacrifices for others.
D) Because it requires you to focus entirely on being useful to society in everything you do, act utilitarianism requires you to give up interests that are not directly useful, such as arts and music.