I believe the answer is B, an extended metaphor.
It can't be A because similes are comparing two unlike things using the words "like" or "as", which will also eliminate D.
It can't be C because a personification is where an inanimate object is given human-like qualities.
Throughout the entire passage, the author compares Ben to a bear and uses words such as "growled", "barked", "lumbered" which shows how the comparison between the two is prolonging throughout the passage.
