Critical Reasoning

[BTGmoderatorRO]

Marriages where one spouse's energy levels differ markedly from those of the other spouse were the subject of a research study, which showed that such couples have more fights and fewer friendly conversations with each other as compared to marriages where both spouses exhibit similar energy levels. Thus, mismatched energy levels can seriously threaten the viability of a marriage

Which of the following, if true, most seriously weakens the argument to the left?

a)Fights that can threaten a marriage are occasionally seen even between couples where both spouses have similar energy levels.
b)People's energy levels fluctuate with seasons and times of day
c)Spouses with energy levels significantly different from those of their spouses usually fight very infrequently with coworkers.
d)It was discovered that people in unhappy marriages assume different energy levels from their spouses as a passive-aggressive way of showing dissatisfaction.
e)Energy levels can be moderated and even changed easily by most people, as shown by another study.

OA is D
I couldn't get the appropriate answer to this question. Please, I need the help of an Expert here. Thanks in advance.

[DavidG@VeritasPrep]

Marriages where one spouse's energy levels differ markedly from those of the other spouse were the subject of a research study, which showed that such couples have more fights and fewer friendly conversations with each other as compared to marriages where both spouses exhibit similar energy levels. Thus, mismatched energy levels can seriously threaten the viability of a marriage

Which of the following, if true, most seriously weakens the argument to the left?

a)Fights that can threaten a marriage are occasionally seen even between couples where both spouses have similar energy levels.
b)People's energy levels fluctuate with seasons and times of day
c)Spouses with energy levels significantly different from those of their spouses usually fight very infrequently with coworkers.
d)It was discovered that people in unhappy marriages assume different energy levels from their spouses as a passive-aggressive way of showing dissatisfaction.
e)Energy levels can be moderated and even changed easily by most people, as shown by another study.

OA is D
I couldn't get the appropriate answer to this question. Please, I need the help of an Expert here. Thanks in advance.

This is a classic causality argument. The initial argument is, in essence that differing energy levels causes marital problems. If, however, it were true that marital problems caused differing energy levels - that cause and effect were reversed - the argument would no longer be valid. This is what we see in D. If differing energy levels are the result of an unhappy marriage, there's no reason to believe that disparate energy levels are responsible for marital problems.