Answer:
C. The government pays farmers $100 per ton of wheat produced.
Step-by-step explanation:
Subsidy is grant/ financial aid given by government to producers of a commodity, to enable its availability in markets at a lower price.
Government paying farmers $100 tone per wheat produced is a subsidy as : It is a financial assistance given by government to reduce wheat's price in markets.
Bank's low interest rate to farmers is just credit ease policy ; Govt putting a tax on wheat imports is opposite of subsidy ; Farmer paying govt $100 per unit wheat is also a form of tax (opposite to subsidy).