Second paragraph, 6th line. During Jackson's tenure party, commercialization etc became widely accepted.

Option A on the other hand states that Jackson's supporters did not support the commercialization etc etc... Hence is our answer.

I see D and E as trick answer choices that pretend to provide support by giving you info on the opposite side of the equation. As D states, southerners do not support Jackson because they opposed the development of the commercial economy. Does that mean the opposite is true for northerners (that they support development)? Not necessarily. If the facts aren't found in the text, then you can't make that call.

Same for E. Since Jackson did not feel as strongly committed to the classical ideals of leadership of GW, it is the opposite true (that he supported political parties)? Making the assumption that the opposite is true is taking a blind leap. Again, if the facts aren't found in the text, then you can't make that call.

Not sure if I'm off base here, but that's my take.[/spoiler]