3)Which formula is correctly paired with its name

3)Which formula is correctly paired with its name?
1)NaCl, Sodium Chlorate
2)AgBr, silver bromide
3)S(subscript 2)O(subscript 4), Trisulfur Trioxide
4) What is the name of a compound whose formula is OF(subscript 2)?
2) oxygen fluoride
3) monoxygen difluoride
4) oxygen difluoride