The biggest misconception about Critical Reasoning questions on the GMAT® is that they are based on common sense. Well, nothing could be farther from the truth. In fact, CR questions are based on rules of formal logic. The question from the Official Guide (OG) below is a perfect illustration. A study of marital relationships in which one partner’s sleeping and waking cycles differ from those of the other partner reveals that such couples share fewer activities with each other and have more violent arguments than do couples in a relationship in which both partners follow the same sleeping and waking patterns. Thus, mismatched sleeping and waking cycles can seriously jeopardize a marriage. Which of the following, if true, most seriously weakens the argument above? (A) Married couples in which both spouses follow the same sleeping and waking patterns also occasionally have arguments that can jeopardize the couple’s marriage. (B) The sleeping and waking cycles of individuals tend to vary from season to season. (C) The individuals who have sleeping and waking cycles that differ significantly …