Final answer:
The detail indicating the author's disagreement with Rod Jex's school arrangement is that Jex filed a complaint to get a sign language interpreter, showing he was dissatisfied with just having lecture notes. The correct option is D. Jex filed a complaint and was able to arrange for a sign language interpreter.
Step-by-step explanation:
The detail that best shows that the author disagreed with the arrangement that Rod Jex's school made for him at first is Jex filed a complaint and was able to arrange for a sign language interpreter.
This action implies dissatisfaction with the initial arrangement, which was likely the school's offer to provide him only with teachers' lecture notes or transcripts of earlier lectures. By taking the step to file a complaint, Jex actively sought to rectify a situation he found unacceptable, thereby demonstrating his disagreement with the school's original provisions for his education.