You need another comma after the word "think" because it's a parenthetical expression and is set off from the sentence.
An income tax system in which a persons tax rate is the same regardless of taxable income.
Coming from a sheriff who i assume has a kind heart. It means there's certain actions that have to take place in order to keep yourself and others safe even though it might not be the kindest or right decision.
The answer is E.
steep, descent