“There is a game of puzzles,” he resumed, “which is played upon a map. One party playing requires another to find a given word—the name of town, river, state or empire—any word, in short, upon the motley and perplexed surface of the chart. A novice in the game generally seeks to embarrass his opponents by giving them the most minutely lettered names; but the adept selects such words as stretch, in large characters, from one end of the chart to the other. These, like the over-largely lettered signs and placards of the street, escape observation by dint of being excessively obvious; and here the physical oversight is precisely analogous with the moral inapprehension by which the intellect suffers to pass unnoticed those considerations which are too obtrusively and too palpably self-evident. But this is a point, it appears, somewhat above or beneath the understanding of the Prefect. He never once thought it probable, or possible, that the Minister had deposited the letter immediately beneath the nose of the whole world, by way of best preventing any portion of that world from perceiving it.

Question

One of the author’s purposes in the story is to portray a mystery as an intellectual game. How effectively does the author use text structure in this passage to fulfill this purpose?

a. The summary ineffectively adds information that is not related to the mystery or how Dupin solved it.
b. The summary ineffectively skips over details that the reader needs to understand the mystery.
c. The summary effectively increases the pace to challenge readers' thinking.
d. The summary effectively reduces the tension of the mystery and re-focuses readers on a puzzle.

I know its not a or b. pls help