2.
Your Answer is
Correct Answer is J
Explanation
The last sentence "For example, although ancient Koreans and Nordics had different kinds of irons, they both used smooth surfaces to iron clothes." The second sentence "Koreans used flat plates of stone". There is no strong logical relationship between the preceding and following sentences, so no correlatives are needed. on the other hand refers to the other side of a thing. be that as it may: nonetheless. by now: So far. Neither fit the title.