我知道C不对，但是解释感觉不太清楚，能从x-m=(s-i)+(t-g)的角度解释吗？
问题如下图：
选项：
A. 
B. 
C. 
解释：
NO.PZ2016010802000194 问题如下 Whiof the following chronic ficit contions is least alarming to the ficit country’s cretors? A.High consumption. B.High private investment. C.High government spenng. is correct.A current account ficit ten to result from low private saving, high private investment, low government savings, or a combination of the three. Of these choices, only high investments cincrease proctive resources animprove future ability to repcretors.考点Tra Balance.解析私人投资领域和科技以及生产资源相关。这些投资在未来能带来极大的回报。比如外溢效益，以及科技对于生产的推动。所以政府即便现在是债务人，在未来它也能还得起债务，无需担心。而A,C就没有这个功效，所以不入选。 以下哪种长期赤字状况对赤字国家的债权人来说最不令人担忧？赤字国家债券不担忧，换个方式理解，就是贸易赤字减少即X-M增加。也就是债权人并不担忧？那为什么跟X-M增加到一起了呢？没有懂逻辑链
NO.PZ2016010802000194问题如下Whiof the following chronic ficit contions is least alarming to the ficit country’s cretors?A.High consumption.B.High private investment.C.High government spenng. is correct.A current account ficit ten to result from low private saving, high private investment, low government savings, or a combination of the three. Of these choices, only high investments cincrease proctive resources animprove future ability to repcretors.考点Tra Balance.解析私人投资领域和科技以及生产资源相关。这些投资在未来能带来极大的回报。比如外溢效益，以及科技对于生产的推动。所以政府即便现在是债务人，在未来它也能还得起债务，无需担心。而A,C就没有这个功效，所以不入选。 老师为什么A 不能用BT＝Y-E这个公式呢？ E＝C+I+G. C增加E增加，BT不就是会减少吗？
NO.PZ2016010802000194 问题如下 Whiof the following chronic ficit contions is least alarming to the ficit country’s cretors? A.High consumption. B.High private investment. C.High government spenng. is correct.A current account ficit ten to result from low private saving, high private investment, low government savings, or a combination of the three. Of these choices, only high investments cincrease proctive resources animprove future ability to repcretors.考点Tra Balance.解析私人投资领域和科技以及生产资源相关。这些投资在未来能带来极大的回报。比如外溢效益，以及科技对于生产的推动。所以政府即便现在是债务人，在未来它也能还得起债务，无需担心。而A,C就没有这个功效，所以不入选。 ppt的哪一页？对应什么知识点
NO.PZ2016010802000194 问题如下 Whiof the following chronic ficit contions is least alarming to the ficit country’s cretors? A.High consumption. B.High private investment. C.High government spenng. is correct.A current account ficit ten to result from low private saving, high private investment, low government savings, or a combination of the three. Of these choices, only high investments cincrease proctive resources animprove future ability to repcretors.考点Tra Balance.解析私人投资领域和科技以及生产资源相关。这些投资在未来能带来极大的回报。比如外溢效益，以及科技对于生产的推动。所以政府即便现在是债务人，在未来它也能还得起债务，无需担心。而A,C就没有这个功效，所以不入选。 求问老师这道题为什么不选A？
NO.PZ2016010802000194问题如下Whiof the following chronic ficit contions is least alarming to the ficit country’s cretors?A.High consumption.B.High private investment.C.High government spenng.is correct.A current account ficit ten to result from low private saving, high private investment, low government savings, or a combination of the three. Of these choices, only high investments cincrease proctive resources animprove future ability to repcretors.考点Tra Balance.解析私人投资领域和科技以及生产资源相关。这些投资在未来能带来极大的回报。比如外溢效益，以及科技对于生产的推动。所以政府即便现在是债务人，在未来它也能还得起债务，无需担心。而A,C就没有这个功效，所以不入选。为什么政府支出不能像私人投资一样促进经济？
