Concept:The Malthusian theory assumes that food production grows only arithmetically while population grows geometrically, so it fails mainly because technology can raise food supply.
Explanation:Malthus predicted that population growth would outstrip food supply and cause famine.
Modern economies have overcome this problem largely through technical progress.
Advances in farming methods, machinery, fertilisers, irrigation, and transportation have greatly increased food output.
These innovations allow food production to grow faster than Malthus assumed.
Birth control measures and government policies can help manage population growth, but they do not directly challenge the food-supply assumption as strongly as technology does.
Natural disasters actually support the Malthusian idea rather than make it ineffective.
Therefore, the main reason the theory is ineffective in modern economies is technological improvement.
Answer:B. technical progress