The title "two kinds" refers to
a. the customs of china and america
b. the contests the narrator enters
c. types of daughters
d. names of songs

It's very interesting to read the short story and see how the title adopts different meanings throughout the plot. But, among the possible options, the best one would be option D, as two kinds refers to the songs she encounters in the story; "Pleading Child" and "Perfectly Contented". However, at the same time, these two songs (which are actually two parts of a whole song) are a reflection of the two kinds of daughters that the main character could have been towards her mother, and reflect the lesson that our protagonist had to learn.

But still, the simplest and most appropriate answer would be D.