A student always tells the truth on Mondays and Tuesdays but always tells lies on Saturdays. On the other days of the week he tells the truth or tells lies, at random. For six consecutive days he was asked what his first name was, and he gave the following answers, in order: Jack, Bill, Jack, Bill, Peter, Bill. On what day of the week did he answer Peper? 
选项为:A:Wednesday  B:Thursday  C:Friday  D:Saturday  E:Sunday  请回答其中一个选项.