Explanation

The “although” that begins the second sentence suggests that there is a contrast between the way the naked eye perceives the patterns in question and the way computer programs can view them. The answers to Blank (ii) and Blank (iii) must therefore reflect this contrast. “Invisible” and “detected” are the only pairing that does this. Blank (i) calls for a characterization of the relationship between the researchers and the inevitability of imperfections in printing technology. Since the passage asserts that researchers are using computers to analyze these imperfections, “exploiting” is the best choice for Blank (i). “Facing” does not imply the level of engagement detailed in the passage, while “manipulating” suggests that the researchers’ focus might be on changing the imperfections themselves, rather than analyzing them. Thus the correct answer is exploiting (Choice A), invisible (Choice D), and
detected (Choice G).