Answer: Pb2+(aq) and Ni2+ ---- B
Explanation:A salt bridge is a laboratory device used in an electrochemical cell to connect the oxidation ( which occurs at the anode ) and reduction( which occurs at the cathode) half-cells of a galvanic cell voltaic cell, It prevents the cell from quickly reaching equilibrium by maintaining electrical charge neutrality within the internal circuit because the electrons are moving from one-half cell to the other.
In this electrochemical cell, Ni (s) is oxidized to Ni2+(aq) and will occurs at the anode while Pb2+(aq) is reduced to Pb (s) and will occur at the cathode.