A．Age, income and education.B．Age, gender and income.C．……

Today, cigarette smoking is a common habit. About forty-three percent of the adult men and thirty-one percent of the adult women in the United States smoke cigarettes regularly. It is encouraging to see that millions of people have given up smoking.
It is a fact that men as a group smoke more than women. Among both men and women the age group with the highest portion of smokers is 24～44.
Income, education, and occupation all play a part in determining a person"s smoking habit. City people smoke more than people living on farms. Well-educated men with high incomes are less likely to smoke cigarettes than men with fewer years of schooling and lower incomes. On the other hand, he is likely to smoke packs of cigarettes per day.
This situation is somewhat different for women. There are slightly more smokers among women with higher family income and higher education than among the lower income and lower educational groups. These more highly educated women tend to smoke more heavily.
Among teenagers the picture is similar. There are fewer teenaged smokers from upper- income, well-educated families, and fewer from families living in farm areas. Children are most likely to start smoking if one or both of their parents smoke.What factors determine a person"s smoking habits

A．Age, income and education.
B．Age, gender and income.
C．Occupation, income and gender.
D．Occupation, income and education.