问题如下：
Based on Exhibit 2 and Note 2, the change in Ambleu’s consolidated income tax rate from 2016 to 2017 most likely
resulted from a:
选项：
A.decrease in Ambleu’s domestic tax rate.
B.more profitable business mix in its subsidiaries.
C.stronger Norvoltian krone relative to the currencies of its subsidiaries.
解释：
B is correct.
The consolidated income tax rate is calculated as income tax expense divided by profit before tax. Note 2 shows that Ambleu’s consolidated income tax rate decreases by 2.29%, from 34.94% (=94/269) in 2016 to 32.65% (=96/294) in 2017. The largest component of the decrease stems from the 1.42% change in the effect of tax rates in non-domestic jurisdictions, which lowers Ambleu’s consolidated income tax rate in 2016 by 3.34% (=9/269) and in 2017 by 4.76% (=14/294). The decrease in 2017 could indicate that Ambleu’s business mix shifted to countries with lower marginal tax rates, resulting in a lower consolidated income tax rate and more profit. (The change could also indicate that the marginal tax rates decreased in the countries in which Ambleu earns profits.)
解析：题目问有效税率的变化是因为哪个原因。可以分别计算出2016年和2017年集团的有效税率：2016年是94/269=34.94%，2017年是96/294=32.65，变化趋势是有效税率降低了。
单独计算一下母公司的税率：2016年是92/269=34.2%，2017年是102/294=34.7%，可以看到母公司国家的税率是在增加的，A选项错误。再看一下外国子公司的业务给集团带来的税收好处：2016年是9/269=3.34%，2017年是14/294=4.76%，说明由于子公司运营给集团税收带来了更多的税收减少的好处，B选项正确。C选项是凑选项的，汇率和税率无关。
老师，解析里“再看一下外国子公司的业务给集团带来的税收好处：2016年是9/269=3.34%，2017年是14/294=4.76%，说明由于子公司运营给集团税收带来了更多的税收减少的好处”，没看懂因果关系，麻烦解释一下，谢谢！
