Which line most contributes to the tone of wistful reflection in the last stanza of robert frost’s "the road not taken”? i shall be telling this with a sigh somewhere ages and ages hence: two roads diverged in a wood, and i – i took the one less traveled by,'

The correct answer is - I shall be telling this with a sigh. Wistful reflection means that he is thinking about something from the past that makes him sad or nostalgic or regretful. When we sigh it can mean several things, one of them is an indication that we are reflecting on something that brings up different emotions.