To be a good friend, you have to give of y

问题：

To be a good friend, you have to give of yourself, nonetheless not so much that you lose yourself. This is a pretty predictable recipe for happiness. Giving to others—a reliable way of fostering friendships—makes us happier than taking things for ourselves. In the light of research led by Dr. Elizabeth Dunn at the University of British Columbia, money can purchase happiness...on the prerequisite that you utilize it on other people.

Researchers administered three studies consecutively. First, they surveyed more than 600 Americans and found that spending money on gifts and charities led to greater happiness than spending money on oneself.

Subsequently they probed into workers who had just received bonuses and observed that their happiness did not hinge on the size of their bonus but on the decision they made about what to do with whatever amount of money they received. Those who spent more of their bonus on others were happier than those who spent the money on themselves.

Finally, the researchers simply distributed money to a good many subjects, instructing some to spend the money on themselves and others to spend the money on others. At the end of the day, the ones who spent money on others were a good deal happier.

As a consequence, having friends and treating them generously is clearly a winning strategy in life. But what about in business

If you watch even a single episode of any reality TV show based on a competition, such as The Apprentice, you’ll hear a single phrase crop up more often than any other: "I’m not here to make friends!" Is that true Are we better off being cutthroat than collaborative

Once you’re on the job, having a best friend at work is a p predictor of ensuing success. People might define "best" loosely (think of this as kindergarten where you can have more than one "best" friend), but according to a Gallup Organization study of more than 5 million workers over 35, 56% of the people who say they have a best friend at work are engaged, productive, and successful while only 8% of the ones who don’t are.

Another remarkable study, spanning decades, revealed that friendships in high school were an effective predictor of increased wages in adulthood—to the tune of 2% per person who considered you a close friend. To put it otherwise, if in high school three people regarded you as one of their closest same-sex friends, your earnings in adulthood work would be 6% higher.

The happy truth is that the competitors who say they’re not here to make friends don’t win eventually. That’s true for reality TV, for business, and for life as well.

Which of the following is true of the three consecutive studies（）

A. Money doesn’t matter when it comes to cultivating friendship

B. The size of one’s bonus makes no difference to the one concerned

C. Giving money to strangers can bring us happiness

D. Money spent on others can bring us much happiness