Read this sentence from Paragraph 4 of the passage.
When the apprentice has become pretty thoroughly acquainted
with the river, he goes clattering along so fearlessly with his
steamboat, night or day, that he presently begins to imagine that
it is his courage that animates him; but the first time the pilot
steps out and leaves him to his own devices, he finds out it was
the other man's.
Which word could replace the word imagine and most
drastically change the meaning of the sentence?
O believe
O think
O pretend
O assume