Concept:Development plans often fail because underdeveloped countries depend heavily on exporting primary products with poor returns.
Explanation:Underdeveloped countries mainly export primary products such as raw materials and agricultural goods.
These products earn low and unstable income in the global market.
The money earned is largely used to import expensive manufactured goods from developed countries.
Therefore, little revenue remains for funding development projects.
This weakens the implementation of development plans and prevents them from reaching their objectives.
The other options are not as directly linked to this common problem.
Answer:B. Exportation of more primary products