10. Firm X produces output x and Firm Y produces output y using capital, K, and labor, L, as inputs. Firm X has marginal rate of technical substitution MRTS*KL = K,/L. while firm Y has marginal rate of technical substitution MRTS' KL = 9K, Ly. Which of the following allocations satisfies input efficiency? A. Firm X has 5 units of K and 3 units of L, and Firm Y has 3 units of K and 1 unit of L. B. Firm X has 5 units of K and 5 units of L, and Firm Y has 1 unit of K and 9 units of L. C. Firm X has 9 units of K and 1 units of L, and Firm Y has 5 units of K and 5 units of L. D. Firm X has 5 units of K and 5 units of L, and Firm Y has 1 unit of K and 3 units of L