Explanation
Correct answer: C.
Choice C is the best answer. "More often" logically signals that the claim in this sentence—that new via ferratas favor recreation over utility—explains a difference between the new "sporting activity" routes and the older "mode of travel" routes. In so doing, it emphasizes and reinforces the previous claim ("modern via ferratas are rarely designed to simply reach a summit").
Why the other choices are wrong
Choice A
Choice A is incorrect because "additionally" illogically signals that this sentence’s claim about new via ferratas adds a new, separate point to the previous claim ("modern via ferratas are rarely designed to simply reach a summit"). Instead, the second claim—that new routes favor recreation over utility—emphasizes and reinforces the previous one.
Choice B
Choice B is incorrect because "on the other hand" illogically signals that this sentence’s claim about new via ferratas contrasts with or opposes the previous claim ("modern via ferratas are rarely designed to simply reach a summit"). Instead, the second claim—that new routes favor recreation over utility—emphasizes and reinforces the previous one.
Choice D
Choice D is incorrect because "nonetheless" illogically signals that this sentence’s claim about new via ferratas is true despite the previous claim ("modern via ferratas are rarely designed to simply reach a summit"). Instead, the second claim—that new routes favor recreation over utility—emphasizes and reinforces the previous one.