【单选题】

Like many lovers of books, Mary and her husband, Richard Goldman, seldom walked past a bookstore without stopping to look inside. They often talked of opening their own store one day.

When Mary was hospitalized with heart trouble in 1989, they decided it was time to get serious. Richard, who worked for a business company, was eager to work for himself, and Mary needed to slow down from her demanding joB、
They started by talking to bookstore owners and researching the industry. "We knew it had to be a specialty store because we couldn’t match the big chains dollar for dollar," says Mary. One figure caught her attention: She’d read somewhere that roughly 20 percent of books sold were mysteries (推理小说), and many buyers spent more $300 a year on books. She and Richard were themselves mystery readers.
On Halloween 1992, they opened the Mystery LoversBookshop andCafé near their home. With three children in college, the couple could not spend all the family’s money to start a shop. To cover the $100 000 cost, they drew some of their savings, borrowed from relatives and from a bank.
The store merely broke even in its first year, with only $120 000 in sales.But Mary was always coming up with new ways to attract customers. The shop had a coffee bar and it offered gifts to mystery lovers and served dinners for book clubs that met in the store. She also invited dozens of writers to discuss their stories.
Today Mystery Lovers makes sales of about $420 000 a year.After paying taxes, business costs and the six part-time sales clerks, Richard and Mary together earn about $34 000.
"The job you love may not go hand in hand with a million-dollar income," says RicharD、"This has always been about an enjoyable life for ourselves, not about making a lot of money.\
According to Richard, the main purpose of running the bookstore is______.A．to pay for their children’s education
B．to get to know more writers
C．to set up more bookstores
D．to do what they like to do