textbook page 23-Q8 题干和题目详见 书本第23页第8题: (A farmer grows wheat.....) a. What is GDP in this economy? b. Calculate the value added of each of the three producers. c. What is the total value added in this economy? How does it compare to the economy's GDP? Does it suggest another way of calculating GDP? (请展示计算过程和答案,可以平台在线作答,或,拍照上传清晰可辨认的图片)