The quote suggests that widespread disease can negatively impact the ability of individuals, particularly in rural areas and farming, to work and contribute to the economy. Therefore, the most appropriate answer to how widespread disease affects the country's economy, based on the quote, would be:
A. It can hurt the economy by removing people from the workforce.
This choice aligns with the idea that diseases like guinea worm incapacitate individuals, preventing them from farming and providing food for their families, which ultimately affects the economy.