Question: what is the surface when the opponent is Selma Babic?
SQL: SELECT "Surface" FROM "2-16893837-3" WHERE "Opponent" = 'Selma Babic';

Question: what is the surface when the round is GII Play-offs and the edition is 2009 Fed Cup Europe/Africa Group II?
SQL: SELECT "Surface" FROM "2-16893837-3" WHERE "Round" = 'GII Play-offs' AND "Edition" = '2009 Fed Cup Europe/Africa Group II';

Question: what is the date when the surface is Clay and the result is 6–7 (4–7) , 1–6?
SQL: SELECT "Date" FROM "2-16893837-3" WHERE "Surface" = 'Clay' AND "Result" = '6–7 (4–7) , 1–6';

Question: who is the opponent when Norway is against?
SQL: SELECT "Opponent" FROM "2-16893837-3" WHERE "Against" = 'Norway';