The argument says that parents should not be given choices on what is taught to their kids in nursery school. The argument then tries to support this assertion by claiming that if such parents are given choices, they are never happy. An example of this kind of behavior follows. Lets examine each one of the choices to see which one fits the bill in identifying the flaw in the argument.
(A): The argument does not mention any ideas advocated by opponents, so misrepresenting such ideas is out of the question. Incorrect.
(B): The conclusion is that parents should not be given choices on what their kids study in nursery school, and the supporting premise is that the parents who are given this information are never happy. It is the premise that leads to the conclusion, and not the other way round. Incorrect.
(C): Rather than discussing the idea, the argument does attack the people who support it. CORRECT.
(D): The definition of 'happy' is clear here, and does not constitute a flaw in the argument. Incorrect.
(E): The stimulus in fact summarizes a position that supports the argument, not one that the argument discredits. Incorrect.
(C) it is.