Anyone who has ever lost keys or money will have wished for a simple but effective way to make sure it never happens again. A US company is trying to help. Using a tiny microchip which is implanted into the arm, they have come up with a replacement for cash or credit cards that cannot be left at home or dropped on the bus. The Verichip is about the size of a grain of rice and works using radio frequency identification technology. At a shop, a radio frequency "reader" would send a signal and the chip in your arm would respond with your unique identity number. That would give the "reader" your financial information, and money could be taken directly from your accounts and you wouldn't even have to reach for your wallet. The company also hopes to include other information on the chip, such as medical records, building security codes   and passwords, making life even easier. But not everyone is happy with the developments. Critics say that a lot can go wrong with the chip. A clever thief could build a fake   reader that would steal your information without you knowing. So your money could still be stolen. Privacy is a big issue too. Stores, or even the government, only need to track the chip to find out what you buy, how much you spend and where you go. And if you wanted to get rid of your chip, you would need an operation to remove it. The Verichip is   _  .
the identity number the security code a tiny microchip a radio reader
Question: Anyone who has ever lost keys or money will have wished for a simple but effective way to make sure it never happens again. A US company is trying to help. Using a tiny microchip which is implanted into the arm, they have come up with a replacement for cash or credit cards that cannot be left at home or dropped on the bus. The Verichip is about the size of a grain of rice and works using radio frequency identification technology. At a shop, a radio frequency "reader" would send a signal and the chip in your arm would respond with your unique identity number. That would give the "reader" your financial information, and money could be taken directly from your accounts and you wouldn't even have to reach for your wallet. The company also hopes to include other information on the chip, such as medical records, building security codes   and passwords, making life even easier. But not everyone is happy with the developments. Critics say that a lot can go wrong with the chip. A clever thief could build a fake   reader that would steal your information without you knowing. So your money could still be stolen. Privacy is a big issue too. Stores, or even the government, only need to track the chip to find out what you buy, how much you spend and where you go. And if you wanted to get rid of your chip, you would need an operation to remove it. The Verichip is   _  .
A. the identity number
B. the security code
C. a tiny microchip
D. a radio reader
Answer: