Q4) kindly read the table and answer the question in the bottom. Thanks

Point Production of grain(tons) Production of cars(cars) A 0 30 B 2 28 C 4 24 D 6 18 E 8 10 F 10 0 The above table shows production points on production possibilities frontier for grain and cars. If the country wants to produce 4 tons of grain a day, how many cars must it produce to achieve the production efficiency