18) In a small European country, it is estimated that changing the level of capital from $8 million to $10 million will increase real GDP from $2 million to $3 million If the number of hours worked in the labor force does not change, what does this information tell you about the slope of the per-worker production function in this range? A) The slope is -2. B) The slope is 1J2. C) The slope is 2. D) The slope is 4