“Such self-reliance is a principal value of child rearing in middle-class America” means that
A.
The mainstream of American culture values much about the spirit of self-reliance.
B.
American in middle-class values self-reliance as a basic point rather than upper or lower class.
C.
Top-class in America dose not care about self-reliance.
D.
Self-reliance is valued topmost first in middle-class, then second in lower-class.