Q68593 - CESGRANRIO - 2010 - Petrobrás - Administrador - Biocombustível,

"This challenge" in "This challenge will have a longer term effect on our economies..." (lines 43-44) refers to the

a) uncertainty about the future of the global economy.
b) unclear estimation of oil reserves reported by the government.
c) low carbon emissions resulting from conventional oil extraction.
d) political and financial interests of the world's economic leaders.
e) confrontation of the unpleasant situation of oil shortage in the near future.

Inglês