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?

• AMarried couples in which both spouses follow the same sleeping and waking patterns also occasionally have arguments than can jeopardize the couple's marriage.  
• BThe sleeping and waking cycles of individuals tend to vary from season to season.  
• CThe individuals who have sleeping and waking cycles that differ significantly from those of their spouses tend to argue little with colleagues at work.  
• DPeople in unhappy marriages have been found to express hostility by adopting a different sleeping and waking cycle from that of their spouses.  
• EAccording to a recent study, most people's sleeping and waking cycles can be controlled and modified easily.