Dick was born in a poor family. His father

问题：

Dick was born in a poor family. His father had a small boat and went fishing in the morning and sold the fish in the market in the afternoon. Then he bought some food for his family. When winter came, they were often hungry. One morning the hungry man fell into the river and wasn’t found. Dick’s mother left her three-year-old son without saying good-bye. His aunt had to look after him.
Twenty years passed. Dick became a tall, p man. He found work on a farm. He worked hard and wanted to get more money. He often went to see his aunt with some nice presents. The woman was very happy but one day she died in a traffic accident. The young man was very sad. After he buried her, he decided to buy a beautiful tombstone(墓碑)for her. He went to town and came in a shop, but all the tombstones were too expensive. He asked, "Do you sell an old tombstone, sir" "Yes, we do, sir," answered the shopkeeper. "Is it as expensive as the new one"
"No, it’s much cheaper," said the man. "But another name was engraved (刻) on it." "It doesn’t matter," said Dick. "My aunt couldn’t read.\

Dick wanted to buy an old tombstone because ______.

A．he didn’t have enough money to buy a new one

B．his aunt couldn’t read whose name was engraved

C．his aunt wasn’t going to mind it

D．nobody knew what his aunt’ s name was