What is mainly discussed in the passage?

Câu hỏi: Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 35 to 42.
For decades doctors have warned us about the danger of stress and have given advice about how to cut down our stress levels. Everyone agrees that long-term stress, for example having to look after someone who has a chronic illness, or stressful situations where there is nothing we can do, for example being stuck in a traffic jam, is bad for our health and should be avoided whenever possible. However, some medical experts now believe that certain kinds of stress may actually be good for us.
Dr Marios Kyriazis, an anti-ageing expert, claims that what he calls "good stress" is beneficial to our health and may, in fact, help us stay young and attractive and even live longer. Dr Kyriazis says that "good stress" can strengthen our natural defences which protect us from illnesses common among older people, such as Alzheimer's, arthritis, and heart problems. He believes that "good stress" can increase the production of the proteins that help to repair the body's cells, including brain cells.
According to Dr Kyriazis, running for a bus or having to work to a deadline are examples of "good stress", that is situations with short-term, low or moderate stress. The stress usually makes us react quickly and efficiently, and gives us a sense of achievement - we did it! However, in both these situations, the stress damages the cells in our body or brain and they start to break down. But then the cell's own repair mechanism "switches on" and it produces proteins which repair the damaged cells and remove harmful chemicals that can gradually cause disease. In fact, the body's response is greater than is needed to repair the damage, so it actually makes the cells stronger than they were before.
"As the body gets older, this self-repair mechanism of the cells starts to slow down," says Dr Kyriazis. "The best way to keep the process working efficiently is to "exercise" it, in the same way you would exercise your muscles to keep them strong. This means having a certain amount of stress in our lives." Other stressful activities that Kyriazis recommends as being good stress include redecorating a room in your house over a weekend, packing your suitcase in a hurry to reach the airport on time, shopping for a dinner party during your lunch break or programming your DVD or video recorder by following the instruction manual.
So next time your boss tells you that she wants to see that report finished and on her desk in 45 minutes, don't panic; just thinking of it as "good stress" which will have benefits for your long-term health.
What is mainly discussed in the passage?
A. Health benefits of certain stressful situations.
B. Some stress's ability to make our cells stronger.
C. Doing exercise as one way to avoid stress.
D. Illnesses caused by stress.