(a) The author of this excerpt is proposing that the flat tax is a simpler system than using 893 forms required by the current system.
(b) The currently system is unfair according to the excerpt, explaining how the current progressive tax system discriminates based on the source, use, and level of income.
(c) Switching from a progressive tax system to a flat tax system would lower tax rates and get rid of tax bias. Which is discouragement against saving and investing. The performance in a competitive global economy will better.