A farmer wants to manufacture a special plant nutrition using fertilizers A and B. Each kg of fertilizer A contains 13 units of nitrogen, 5 units of phosphoric acid, 6 units of vitamin A and 5 units of vitamin D. Each kg of fertilizer B contains 8 units of nitrogen, 14 units of phosphoric acid, 6 units of vitamin A and 9 units of vitamin D. To be effective, the plant nutrition requires a minimum 220 units of nitrogen, a minimum of 160 units of phosphoric acid, and no more than 350 units of vitamin A. How many kg of each fertilizer should be used to minimize the amount of vitamin D in the nutrition? What is the minimum amount of vitamin D?