In the context of this excerpt from “civil disobedience” by henry thoreau, what does posterity mean?

Apex english 4 semester 1 read the following story summary. when she was a child, sara hated her piano instructor, mr. singh. she felt she had already mastered the piano, but mr. singh constantly criticized her playing in a blunt and hurtful way. after sara grew up, she realized that mr. singh's strictness was responsible for the only edge she had over other pianists her age and the only reason she was able to succeed in music later in life. she learned to appreciate his tough love. what does the story most clearly suggest about the author's perspective? a.that a person should put his or her talents to good use b.that pursuing one's dream is paramount in life c.that the world is harsh and only the strong survive d.that adults have children's best interests in mind