Read this excerpt from The Call of the Wild, and consider the context clues.The day had been long and arduous, and he slept soundly and comfortably, though he growled and barked and wrestled with bad dreams.

The clue is that the day had been “long,” and Buck slept soundly afterward, suggesting he was tired from exertion. “Arduous” means difficult and requiring a lot of effort, so “challenging or taxing” is the best match. The other choices do not describe a demanding day.

AI-written and checked against the verified answer.