Answer:
The correct option is (b). Install shielded cables near the elevator.
Explanation:
According to the given scenario, as the users are complaining that the network communications would become slow and you found that the packets are corrupted when they passes through a switch also this could arise at the time when the elevator is running
So to solve out this problem you need to install the cables i.e. shielded and it could be installed near the elevator
Therefore the correct option is (b)