Bicycle sharing systems allow users to rent a bicycle at one loion within a city and

Choice C is the best answer because it most logically completes the text’s discussion of Ikeguchi’s model of bicycle supply. In this context, “saturated with” means thoroughly or completely supplied with. The text explains a problem encountered by some bicycle-sharing programs: users can return bicycles to different loions than where the users picked up the bicycles to start, which can result in a mismatch between bicycle supply (that is, where the bicycles are currently loed) and user demand (that is, the loions where users are hoping to pick up bicycles). The text goes on to explain that Ikeguchi developed a way to identify when this mismatch is likely to occur. This context suggests that Ikeguchi’s method will show when it is likely that some loions have an insufficient supply and other loions, by implicit contrast, are saturated with bicycles. 

Choice A is incorrect because nothing in the text suggests that some loions are “susceptible to,” or sensitive to or easily influenced by, bicycles. The text describes the phenomenon of bicycles being redistributed away from loions where users want them, not anything about those loions being influenced by the bicycles. Choice B is incorrect because the text describes situations in which some loions have an insufficient supply of bicycles because the bicycles have been reloed elsewhere, which suggests that the other loions have many bicycles, not that the other loions are “contingent on,” or dependent on, the bicycles. Nothing in the text suggests that the loions themselves depend on the bicycles for anything. Choice D is incorrect because it would not make sense in context to say that some loions are “depleted of,” or empty of, bicycles while others have an insufficient supply. The text describes situations in which bicycles have been reloed such that there is a mismatch between bicycle supply and user demand—the bicycles are no longer at the loions where users want to pick them up. This means that some loions do not have enough bicycles, while other loions must have many bicycles, not be depleted of bicycles.