Mushin gives as much as he can to his local Zen center and volunteers there on a regular basis. He also regularly attends retreats there, during which only limited meals are provided. Furthermore, the teachings there encourage him to be present and attend to all sentient beings. Mushin is experiencing Buddhism's emphasis on __________.
a. making money and getting ahead
b. guilt
c. dominion over all living creatures
d. self-denial and compassion