A supporter of the ideas of Utopian socialist Robert Owen would be most prepared toA supporter of the ideas of Utopian socialist Robert Owen would...

For this question, you really ought to look at what your
particular textbook and/or teacher says about Owen's ideas.  Owen had a number of
different ideas over the course of his life and different texts might emphasize
different aspects of his thought.

The wording of the
possible answers implies that A is the right answer.  A is the only one that makes the
other answers impossible.  A person could, for example, want both B and D.  Such a
person might well want capitalism to spread as well.  A is plausible as a correct answer
because Owen's New Harmony community was a place that was based on socialist ideas and
not on capitalism.  Therefore, this is probably the best
answer.

However, you should be aware that Owen himself was
a factory owner for much of his life.  During that time, he tried to reform the abuses
of capitalism, doing things like proposing laws that the British Parliament might
enact.  During this time of his life, B might be a better
answer.

Based on the choices given, A is probably right,
but you really should check in your text and/or notes.