Tom and his cousin took a boat trip. When they got on the boat, every passenger  should answer the keeper a question. If the passenger answered "yes", he or she got one gift; if the passenger answered "no", he or she got two gifts. Tom and his cousin saw all about this. Now it was their turn. The keeper came up to them and asked, "Are you _ ?" Tom wanted to get two gifts, so he answered "no" loudly, at the same time he said, "I have never been a sailor, how could I be a good sailor." The keeper gave him two gifts. His cousin gave the same answer, so, he got two gifts too. The boat started off. The passengers began to open their gifts. Tom and his cousin did the same. They found that one of the two gifts was a small bottle of drinking water, the other was a seasick tablet  . Tom had a look at a "yes"-passenger's gift. His was a nice chocolate. Tom shouted at the keeper, "We are never seasick. Why do you give us seasick tablets?" Which of the following statements is true?
The keeper cheated   Tom and his cousin. Tom and his cousin didn't understand the question. All the other passengers answered "yes". The keeper didn't want to give Tom and his cousin chocolate