A car gives a mileage of 20 km per liter of petrol when driven at a constant speed of 50 kmph but the mileage decreases by 10% when driven at a speed of 70 kmph. How many km can the car travel with 12 liters of petrol if it travels a speed of 70 kmph?
A. 216 km
B. 240 km
C. 228 km
D. 200 km