Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 19 to 24.

A new study shows that women can reduce their chances of developing heart disease (19) _____ jogging for about three hours every week. The researchers at Harvard Medical University in Boston have just reported the results of the study in the New England Journal of Medicine. The study is the first to show the (20) _____ of jogging in the development of heart disease in women. Only (21) _____ earlier studies have examined the effects of jogging on the heart, but nearly all have been done on men. The new study involves more than 72,000 women between the (22) _____ of forty and sixty-five during a period of eight years. The researchers have found that women (23) _____ jog at least three hours a week have a thirty to forty percent lower chance of having a heart attack (24) _____ those who do not.