A、Men. B、Women. C、Young people. D、Old people. D短文中提到，在所有人群中，60岁及以上的老人在生日时的死亡率是最高的，故答案为D)。

(22)Besides the cards, cake, candles, and gifts, there might be one more unexpected surprise in store for you on your birthday. It’s a higher risk of dying.
    A new study suggests that men and women are 14 percent more likely to die on their birthday than any other day of the year.(23)This effect was strongest in people aged 60 and older, who were up to 18 percent more likely to die on their birthday.
    In the large study, researchers analyzed data from more than 2. 4 million Swiss people who died between 1969 and 2008. They tried to determine if there was any relationship between when people died and the cause compared to their birthdays.
    Both violent causes, such as suicides and falls, as well as strokes and heart diseases were tied to birthdays. In addition, older people are distinctly more vulnerable than younger people.
     (24)Men were more likely to have a violent death on their birthday. It was because their chances of suicides increased by nearly 35 percent and their odds of being accident victims rose by almost 44 percent. Deadly falls in men rose by 44 percent on their birthdays. And the more interesting thing is the number of falls started to increase about four days before the celebration took place.
     (25)When it came to natural causes of deaths, women were at greater risk of passing away from a stroke on their birthday. It reached almost 22 percent. For both ladies and gentleman, there was a nearly 19 percent increase in dying from heart-related reasons.
22. What is the passage mainly about?
23. Which group of people is most likely to die on their birthday?
24. Why were men more likely to have a violent death on birthday?
25. What natural cause of death made women at a greater risk?