Final answer:
Excerpt D is the best example of pathos, as it evokes feelings of sadness through the description of the woman's singing and the mention of the world's saddest song.
Step-by-step explanation:
The best example of pathos can be found in excerpt D: "Finally I lie down and breathe against the weight of unmovable air on my chest. I wake up a few hours later to hear a sound not generated by anyone's TV: a woman's clear alto singing two lines of the world's saddest song, lyrics indecipherable, to the accompaniment of trucks on the highway." This excerpt evokes feelings of sadness and melancholy through the description of the woman's singing and the mention of the world's saddest song.