Irrelevant. It doesn’t matter which course students find most interesting. Just because students find these courses most interesting doesn’t mean that they reflect university education overall.

Irrelevant. Universities whose history courses require books that cover all periods and cultures are likely not representative of “most universities today.” Regardless, we still don’t know whether culturally inclusive history courses reflect a cosmopolitan education.

This suggests that history course material is representative of education overall. In other words, the fact that university history textbooks are more in-depth, cosmopolitan, and culturally inclusive does indicate that university education is also more in-depth and cosmopolitan.

This weakens the argument by suggesting that university history courses are not representative of university education as a whole. If other subjects aren’t more culturally inclusive, the author can’t conclude that university education overall is more in-depth and cosmopolitan.

Irrelevant. (E) doesn’t suggest that students who read textbooks that cover the history of many cultures will get an in-depth and cosmopolitan education. We still need to know whether history course material is representative of overall education.