The analyst is calculating the carbon footprint of a company and notices a significant drop in carbon intensity from the previous year, despite the company's product and the way it is produced remaining unchanged The analyst notes that the government has imposed a new carbon tax during the year, a few months ago the company has outsourced the carbon-intensive part of its production to another company and it has released its second annual report with its ESG metrics assured by a third party Which of the following is a likely explanation for a change in carbon intensity?
选项：

A: Unreliable data caused the drop in carbon intensity
B: Carbon tax increased the cost of carbon emissions and thus resulted in reduction of carbon intensity
C: Metric of carbon intensity are based only on Scope 1 and 2 emissions and excludes Scope 3 emissions
D: Carbon emissions in the previous year have likely been double-counted