A、Becomes useful or helpful. B、Gets something useful or helpful. C、Falls ill. D、Gets hurt. B根据上下文推测benefits在文中的意思应该是有用的或有利的。

You might not know it, but there is something wonderful at your fingertips. You can make people happier, healthier and more hard-working just by touching their arms or holding their bands.
    Doctors say that body touch is a kind of medicine that can work wonders. When people are touched, the quantity of hemoglobin, a type of matter that produces the red color in blood increases greatly. This results in more oxygen reaching every part of the body and the whole body benefits. In experiments, bottle-fed baby monkeys were separated from their mothers for the first ten days of their life. They became sad and inactive. Studies showed the monkeys were more probable to become iii than other babies that were allowed to stay with their mothers.
   Human babies react in much the same way. Some years ago, a scientist noticed that some well-fed babies in a clean nursery became weak. Yet babies in another nursery were growing healthily, even though they ate less well and were not kept as clean. The reason, he concluded, was that they often had touches from nurses.
Experiments show that most people like being touched. And nearly ail doctors believe touch helps to reduce patients’ fear of treatment. Of course there is time when a touch is not welcome. But even if we don’t like being touched, a smile can make as feel better. Smiling increases blood flow and starts the production of “happy brain” chemicals.
    So let’s have a big smile and don’t forget to keep "in touch".