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 from those of their spouses tend to argue little with colleagues at work.
(D) People in unhappy marriages have been found to express hostility by adopting a different sleeping and waking cycle from that of their spouses.
(E) According to a recent study, most people's sleeping and waking cycles can be controlled and modified easily.

i understand this question pretty well and just thought of sharing my explanation:

ok so it is a cause and effect question

mismatched sleeping pattern-->jeopardize marriage

so to weaken this do one of the two things to solve this problem:

-->reverse the cause and effect
-->hunt for alternate cause

in this case D is the reversse the cause and effect......

my question is that is my logic going on the right track or i am really missing out on something here....please share your thoughts guys...