Mr.Tom Forester lived by himself a long way from town.He hardly ever left his home，but one day he went into town to buy some things in the market.After he had bought them，he went into a restaurant and sat down at a table by himself.When he looked around，he saw several old people put glasses on before reading their newspapers，so after lunch he decided to go to a shop to buy himself some glasses too.He walked along the road，and soon found a shop.
The man in the shop made him try on a lot of glasses，but Tom always said，"No，I can't read with these."The man became more and more puzzled （迷惑不解），until finally he said，"Excuse me，but can you read at all？"
"No，of course I can't!"Tom said angrily."If I was already able to read，do you think I would have come here to buy glasses？"

What kind of mistake did Tom make？（）

A.He went to the wrong kind of shop.
B.He didn′t try on all the glasses in the shop.
C.He thought that a person who had not learned to read would be able to do so if he wore glasses.
D.He left his money in the restaurant