A leftward shift in the supply curve indicates a decrease in supply. Among the options provided, the event that would shift the supply curve to the left is:
Local government increases the taxes that are levied on firms.
Higher taxes on firms typically increase their costs of production, which would lead to a decrease in the overall supply of the good. The other options would either not affect supply or would increase it (e.g., reduced input prices or an increase in the number of sellers).
So, the correct response is:
Local government increases the taxes that are levied on firms.