Answer: D. The teacher has misjudged the son's abilities.
Step-by-step explanation:
The author is an Indian father show is trying to get the teacher to understand that his son is not a slow learner but rather an outsider that has to learn a completely new culture from scratch.
The non-Indian children have had a head start in preparing for schooling as they grew up in a society that followed western culture. The Native Indian boy, Wind-Wolf did not and so is new to what is being taught in school. he father is trying to tell the teacher that this is why he is he way he is and that the teacher should not misjudge the boy's abilities.