[单项选择]It’s easy to tell people to make exercise part of their daily routine. It’s not so easy to tell them what to do. Some folks like to run marathons or climb mountains. But if you would rather care for your body without risking life or limbs or increasingly creaky joints, you might consider Tai Chi Chuan, the ancient martial art that looks like a cross between shadow boxing and slow-motion ballet. Tai Chi combines intense mental focus with deliberate, graceful movements that improve strength, agility and — particularly important for the elderly -balance.
Practitioners praise Tai Chi’s spiritual and psychological benefits, but what has attracted the attention of Western scientists lately is what Tai Chi does for the body. In many ways, researchers are just catching up to what tens of millions of people in China and Chinatowns around the rest of the world already know about Tai Chi. Scientists at the Oregon Research Institute in Eugene reported that Tai Chi offers the greatest benefit
A. Healthy but relatively inactive old people.
B. Active but relatively unhealthy old people.
C. Frail old people, just released from hospital.
D. Energetic young people.