what does this mean in english? how can i respond?
i've messaged a seller asking the cost of shipping and they replied "우편 등기 택배 중 어떤걸로 하시겠어요?"
are they asking "what kind of shipping method do you want?" or "do you want registered shipping/shipping with tracking?"
basically i would like the item mailed with tracking aka registered, how would i say that to them?
thanks in advance for your help :)

Question

what does this mean in english? how can i respond?
i've messaged a seller asking the cost of shipping and they replied "우편 등기 택배 중 어떤걸로 하시겠어요?" 
are they asking "what kind of shipping method do you want?" or "do you want registered shipping/shipping with tracking?"
basically i would like the item mailed with tracking aka registered, how would i say that to them?
thanks in advance for your help :)

Answer

It is asking about the preferred delivery method.

"우편 등기 택배 중 어떤걸로 하시겠어요?" 
=> What method would you prefer out of regular mail, registered mail, and private service.

* 우편 = postal mail.
* 등기 = 등기우편 = registered postal mail.
* 택배 = by a private delivery service (this may vary widely).

I believe both 등기우편 and 택배 automatically provides tracking in both countries.

You can answer it like:
- 등기로 보내 주세요 = 등기우편으로 보내 주세요 = Please use the registered mail.
- (조회 가능한) 등기우편으로 보내 주세요 = Please mail it registered (with tracking) - if you want to emphasize tracking.