A group of the world’s richest nations offered South Africa debt guarantees as part of a proposed $8.5-billion deal designed to cut the nation’s reliance on coal for power generation, people familiar with the talks said, potentially resolving one sticking point in the negotiations. The guarantees would enable South Africa or companies such as state power utility Eskom Holdings to borrow money needed to close down coal-fired power plants and enable the generation of renewable energy, one of the people said. The people asked not to be identified as the talks aren’t public.