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。
labor是影响短期供给的因素吧？为什么C不入选呢？
