Always pay close attention to the question. This one asks us what "the author's attitude toward authoritarian regimes is most accurately described as"
The whole passage was geared towards talking about the motivation most authoritarian rulers have for undertaking democratic reforms, and three different changes in society that can occur and serve as the catalyst for bringing about those changes.
The first word in each of these answer choices will tip you off to whether or not they deserve consideration.
(A) "Uncertainty . . ." The author does not express uncertainty in his argument. Also he does not have a discussion about whether the changes are genuine or superficial so that part of the answer choice is unsupported.
(B) "Puzzlement . . ." The author is not puzzled about anything. He is actually confident in his argument. He is especially not puzzled about the motives of most authoritarian rulers as he states plainly in lines 1-7 what the motivation for most authoritarian rulers is.
(C) "Confidence . . . " Yes! He is very confident that changes in societal forces will necessitate a democratic reforms for most authoritarian rulers.
(D) "Insistence . . . " The author would most likely agree with this statement, but it does not describe the author's primary attitude toward authoritarian regimes. Also this is something the author more or less takes for granted in his argument and is not addressed at length or in much detail.
(E) "Concern . . . " He is not concerned at all especially about authoritarian rulers finding way to retain power. He is quite confident that they will bring about their own demise as evidenced by the whole first paragraph and the last paragraph.