BRASILIA (Reuters) - Brazilian airline Gol said on Wednesday that it could resume use of its fleet of Boeing 737 Max jets by year’s end under the most optimistic scenario, according to a securities filing. Gol is Brazil’s sole operator of the trouble-plagued 737 Max. Brazilian aviation regulator ANAC said earlier on Wednesday it was working toward allowing the model to return to operation and that final approval would hinge on Gol demonstrating it adopted relevant safety protocols.