Everyone sitting in the waiting room of the school' s athletic office this morning at nine o' clock had just registered for a beginners tennis clinic. John, Mary, and Teresa were all sitting in the waiting room this morning at nine o' clock. No accomplished tennis player would register for a beginners tennis clinic. It the statements above are true, which one of the following must also be true on the basis of them? ['John, Mary, and Teresa were the only people who registered for a beginners tennis clinic this morning.', "John, Mary, and Teresa were the only people sitting in the waiting room of the school's athletic office this morning at nine o'clock.", 'Neither John nor Teresa is an accomplished tennis player.', "None of the people sitting in the school's athletic office this morning at nine o'clock had ever played tennis."]