9) Last month, an electric meter read 8 985 kWh. This month, the reading is 9 472 kWh. How many kWh was used for one month?

C) 1 513 kWh

To find the amount of kWh used for one month, subtract the previous month's reading from the current month's reading:
9 472 kWh - 8 985 kWh = 487 kWh

Therefore, 487 kWh was used for one month.