Official Explanation
The evils described by this word are more “pernicious,” or harmful, than ... well, it doesn’t even really matter—you want a word like “pernicious.” Perhaps very bad. “Grievous,” which means causing grief or very armful, will work. “Baneful” is an even closer synonym to “pernicious.” Note that you could also find the correct answer by noticing that none of the other four options have a pair in the sentence. “Venerable” means respected, “epicurean” means related to fine food and wine, and “fastidious” means very attentive to detail, all of which have the incorrect tone for the blank. Finally, “reactionary” means opposed to political or social reform, which also doesn’t fit the sentence.
Answer: D,E