Explanation
Correct answer: A.
Choice A is the best answer because as used in the text, "arranged" most nearly means "organized." The text states that a welcome feature of Manchester’s art galleries (as opposed to others) is that the titles of the paintings are easy to see and that a catalogue is therefore unneeded while visitors browse the art galleries. This suggests that the paintings are displayed in a systematic, or organized, way.
Why the other choices are wrong
Choice B
Choice B is incorrect. "Ranked" might mean either classified or placed in orderly rows. Neither of these meanings would necessarily imply that the names of the paintings are easy to see (even if the paintings are placed in rows, their labels might be obscured).
Choice C
Choice C is incorrect because it would not make sense in context to describe the paintings as "scheduled," or planned to take place at a certain time.
Choice D
Choice D is incorrect because if the paintings were "discussed," or talked about, this would have no bearing on whether the names of the paintings could be easily seen.