From the balanced chemical reaction, the ratio of moles of propane to moles CO2 produced is 1/3. Given 2 moles of propane, 6 moles of CO2 is produced. Further, the ratio of moles of O2 to moles of CO2 produced is 5/3. Given 2 moles of oxygen, 1.2 moles of CO2 is produced. We take the smaller amount of CO2 as the answer. Thus, the answer is letter B. 1.2 moles