It is true of both men and women that those who marry as young adults live longer than those who never marry. This dose not show that marriage causes people to live longer, since, as compared with other people of the same age, young adults who are about to get married have fewer of the unhealthy habits that can cause a person to have a shorter life, most notably smoking and immoderate drinking of alcohol.
Which of the following, if true, most strengthens the argument above?
Marriage tends to cause people to engage less regularly in sports that involve risk of bodily harm.
A married person who has an unhealthy habit is more likely to give up that habit than a person with the same habit who is unmarried.
A person who smokes is much more likely than a nonsmoker to marry a person who smokes at the time of marriage, and the same is true for people who drink alcohol immoderately.
Among people who marry as young adults, most of those who give up an unhealthy habit after marriage do not resume the habit later in life.
Among people who as young adults neither drink alcohol immoderately nor smoke, those who never marry live as long as those who marry.