Morgan Rees has always been a good businessman. He used to own three petrol stations and was busy most of the time. When he was 65, the normal retirement age, he decided that he didn't want to stop, so he carried on working for another two years. Eventually, when he was nearly 68, his wife, Dolly, asked him to retire because she wanted to enjoy their old age together. Reluctantly, he handed over the business to his son. But he was unhappy. He didn't know what to do with himself. Although he read a lot of books and he went on holiday to interesting places with his wife, he was bored and began to get depressed because he hated being retired. Then one day he saw an advertisement in the newspaper and, without telling his wife, he bought a small crockery (陶器) factory. The next week he told his family. They were horrified and worried. They thought he was too old at 71 to start work again. He is now 76 and he has expanded the company considerably. He has increased the number of staff from 6 to 24 and he has found many new customers for the products. He has developed the export market and has improved profits by 200%. He has opened a new design office and employed three young designers. They have been all over the world to get new ideas, and one of them has gone to France this week to a major trade fair. Most importantly, he hasn't been bored since he bought the factory.
What is the central idea of the last paragraph? A Morgan Rees has worked until he is 76. B Morgan Rees has developed the export market and improved the profits by 200%. C Morgan Rees hasn't been bored since he bought the factory. D Since he started working again, Morgan Rees has expanded the company considerably, which has enriched his retired life.