请问这道题答案解析标红的地方怎么理解，1，为什么会有这个公式TFP = Labor productivity growth − Growth in capital deepening，怎么理解这个公式，再课上没有提到过 2，从A的解释，A is incorrect because once the economy reaches steady state growth, capital deepening cannot be a source of sustained growth in the economy. 是否可以理解判断reaches steady state growth点就是growth of capital ddeeping=0？
多谢
