XYZ Corp. produces 1,000 units of output (along the same isoquant) using various combinations of capital (K) and labor (L). At point A (along the same isoquant), the firm uses 30 units of capital and 3 units of labor. When it moves to point B (along the same isoquant), it uses 12 units of capital and 6 units of labor. Based on this information, the firm'selasticity of input substition ()is? Hint:You may want to draw a graph of the firm's isoquant and identify points A and B (and their corresponding K/L combinations). a. 1 b. 0 c. 5 d. (positive infinity)