When a negatively charged balloon is brought near the left soda can, it induces a separation of charges within the conductor. The negatively charged electrons in the soda cans will be repelled by the negatively charged balloon, causing them to move away from the balloon.
Since the balloon is near the left can, the negatively charged electrons will move from the left can towards the right can. Therefore, the correct response is:
From the left to the right of the cans.