"'But there isn't a snake!'
'We'll make sure when we go hunting.'
Ralph was annoyed and, for the moment, defeated. He felt himself facing something ungraspable. The eyes that looked so intently at him were without humor.
'But there isn't a beast!'
Something he had not known was there rose in him and compelled him to make the point, loudly and again.
'But I tell you there isn't a beast!'"
Which of the following offers the best explanation of the significance of the use of repetition in the passage above?