Answer: Option (a) is the correct answer.
Step-by-step explanation:
In a voltaic cell, salt bridge is used for connecting oxidation and reduction half cells.
The main purpose of using salt bridge in a voltaic cell is that it helps in maintaining electrical neutrality in the internal circuit occurring at anode and cathode of the cell.
Without salt bridge in a voltaic cell there will be imbalance of charges as a result solution in anode compartment will become positively charged whereas solution in cathode compartment will become negatively charged.
Thus, we can conclude that the salt bridge balances charges that may build up as reduction and oxidation occur in a voltaic cell.