Which one of the following, if true of countries that have gone from a ... ...

Which one of the following, if true of countries that have gone from a graduated progressive tax system to a flat tax, would most support the position of passage B over that of passage A?
(A) Revenues from taxation have remained the same as before.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in PT72 (Jun 2014): Reading Comprehension