问题如下：
Which of the following may not be the reason that the long-run aggregate supply curve shifting to the right?
选项：
A. increase in the supply of natural resources.
B. decrease in the supply of physical capital.
C. increase in the supply of labor.
解释：
B is correct.
An increase in an economy’s accumulated stock of capital equipment will increase potential output——a rightward shift in long-run aggregate supply curve.
考点：长期供给
解析：和成本相关的一类因素会影响短期供给而非长期供给，所以B选项是实物资本属于生产成本，因此不入选。
A选项的自然资源以及C选项的劳动力供给都属于影响长期生产的因素。
physical capital也属于生产资料吧，主要问题是decrease 错了，答案解释有问题
