Answer:
A. student's unwillingness to learn.
Explanation:
"Our Schools are a Scandal" is an article written by Kyle Crichton. The article talks about the educational condition in the US in 1946.
In the given excerpt, the phrase 'silent resistance' describes student's unwillingness to learn. The teacher, in this paragraph, is describing the children (denoted as little demons) who have either become sadistic or adopted a silent resistance– student's unwillingness to learn.
Therefore, option A is correct.