You know that cynics are going to criticize whatever, so as soon
as you think that you should be thinking of a negative verb. Utopian
may seem good, but to a cynic in thiscontext would be foolishly idealistic.
The second half of the sentence also hints at the answer because others
think that the cynics are wrong to “laugh contemptuously at idealism.”
Deride means ridicule so it works (D).