A solution containing Mn�+, Fe�+, Zn�+ and Hg�+ with a molar concentration of 10-� M each is treated with 10-�⁶M sulphide ion solution. Which ions will precipitate first if Ksp of MnS, FeS, ZnS and HgS are 10-�⁵, 10-�� 10-�⁰ and 10-⁵⁴ respectively?(1)FeS (2)MnS(3)HgS(4)ZnS