Questões de Concurso Militar ESCOLA NAVAL 2016 para Aspirante, 2° Dia

Which of the options completes the sentence correctly?

Surveys have found that even though 80% of smokers would like to quit smoking, less than five percent are able to quit on their own ______ the highly addictive properties of nicotine.

(http://www.spine-health.com/we11ness/stop-smoking)