This is a deeply problematic question. The argument essentially says "the poker player was at a tournament 90 minutes from his hometown, therefore he traveled more than 30 minutes to get there". That's a ridiculous argument if you take "hometown" to mean "where someone was born", because why would anyone think this professional poker player still lives in the town where he was born? It's not as ridiculous an argument if you take "hometown" to mean "the town where he makes his home". Then we'd probably want to find some other reason the player might have been in the vicinity of the tournament - maybe he was in the area for a book fair or wine tour or something.
So even the very argument we're trying to weaken hinges on the definition of "hometown". And there is no agreed single definition of that word. From the Merriam-Webster dictionary: "Definition of hometown. : the city or town where one was born or grew up. Also : the place of one's principal residence." If it means "the place of principal residence", then if C is true, he must have moved after the argument in the stem was made (and thus after the tournament took place), and in that case C is irrelevant to the argument overall. If instead it means "the place he was born or raised", then of course C is a good answer, but in that case, it's barely an argument at all.
I'd add that the several replies above that suggest C proves Karet now lives within 30 minutes of the tournament are not correct. Just because he moved more than 60 minutes from Guerra doesn't mean he moved 60 minutes closer to the tournament site. He might have moved to Brazil or Mauritius -- he could be almost anywhere.