Answer: A. The author is making an appeal to ethos by referrig to respected institutions such as the U.S. Congress.
An appeal to ethos is one that relies on the moral advantage that an argument has due to the person who supports it. In this case, the author is telling us that his argument is to be defended because it is supported by institutions such as the U.S. Congress and the Constitution. Congress has established that "Indian Education" is valuable, and the constitution has established the students' rights. This increases the persuasiveness of the argument.