Answer:
D. The high scalers were strong, agile workmen who moved on the equipment-strewn cliffs on ropes, using heavy jackhammer drills, dynamite, and crowbars to remove loose rock from the canyon walls, risking their lives to do so.
Explanation:
remorseful is your best answer
"remorseful" means "filled with remorse, sorry". Even though it is not said, it is implied that he is sorry, because he thinks back to the history of how his mom ended up like that.
hope this helps