Which of the following is a silly mistake of Watson?

Câu hỏi: Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 35 to 42.
In 2011, on the popular American TV quiz show, Jeopardy!, two champions competed against a brand new opponent. Both Ken Jennings and Brad Rutter had won millions of dollars on Jeopardy! Jennings once won 74 games in a row, the most ever. Then Rutter beat him in a tournament and set a new record for the most money won on Jeopardy! Their new opponent, Watson, had never appeared on the game show and had only played practice games before, in which he often got answers wrong.
However, Watson isn't human. He, or rather it, is a machine, a wonder of technology made by researchers at IBM. In the game, Watson used math to decide on an answer. When a question was read out, Watson was immediately given the same question in electronic form. It analyzed the question and searched its memory bank - about the same as one million books of information - for possible answers. It then narrowed the options down to one answer. If Watson felt around 75 percent confident about the answer, it would answer the question.
The way Watson thinks is very different from the way humans think. People often make decisions by listening to their emotions and feelings, even if they are unsure of the answer. As a computer, Watson couldn't do this. People also watch and listen to those around them. Watson was not able to "listen" to the wrong answers given by his competitors. In one question, Jennings answered the question incorrectly and Watson later answered with the same wrong answer. Watson also made silly mistakes. In a question in the category U.S. Cities, Watson incorrectly answered Toronto, even though the city of Toronto is in Canada. An IBM researcher said Watson got confused because it saw in its memory bank that the U.S. is often called America. Toronto is considered a North American city, so that was the answer that Watson gave.
Still, Watson defeated his human opponents somewhat easily and received the $1 million prize. The other players also won money for participating in the special game. Everyone left the game happy, as each player was earning money for different charities.
Which of the following is a silly mistake of Watson?
A. He gave many answers to one question.
B. He based on other people's clues to answer questions.
C. He repeated the question.
D. He repeated his opponent's answer that was wrong.