Which of the Following Was NOT a Reason Why the Signing

Which of the following was NOT a reason why the signing and enforcement of the Montreal Protocol was relatively easy?

A) The scientific evidence about the threat that CFCs posed to the ozone was clear.
B) The production of substitutes for the CFCs appeared to be technologically unfeasible.
C) Production of CFCs was concentrated primarily in a few large publicity-conscious firms in the EU and the U.S.
D) The U.S.and the EU were most likely to be affected by ozone depletion because they are closer to the poles than other countries, and they were also the largest producers.