Global Carbon Emissions in 2010 Were Estimated to Be on the Order

Global carbon emissions in 2010 were estimated to be on the order of 9.0 $\times$ 10¹² metric tons carbon (1 metric ton = 1000 kg) in the form of CO₂.This is equivalent to __________ kg C.

A) about 2.5 $\times$ 10¹⁵ kg
B) about 7.5 $\times$ 10¹⁴ kg
C) about 2.0 $\times$ 10¹⁴ kg
D) about 1.7 $\times$ 10¹³ kg
E) about 1.2 $\times$ 10¹⁵ kg