This points out what's wrong with Frank’s assumption. While innovation may require more technical knowledge than it used to, an innovator doesn’t necessarily need formal education to gain that knowledge. (A) describes a possibility that undermines Frank's assumption.

This is irrelevant. Frank concludes that formal education is now a requirement for innovation, which is something that could be true regardless of whether formal education has improved.

Frank uses the term “crucial” in the same way as Maria since he directly responds to her conclusion. Both individuals refer to the same kinds of contributions.

The argument doesn’t presume this, and it wouldn’t be relevant anyway. Frank’s conclusion is just about what’s required in the modern day, so it doesn’t matter how productive other past inventors were.

Frank actually does address what Maria says about Edison. He implicitly acknowledges that Edison made contributions without a formal education, but draws a distinction between what was required in his time and what’s required today.