Correct Answer: Laterite soil

Solution : The correct answer is laterite soil.

Laterite soil is the most infertile soil among the following. It is found in tropical areas and his formed by the intense leaching due to heavy rainfall. Because of heavy rainfall dissolved elements like lime and silica is wash away and elements like iron oxide and aluminium is present in concentration. Alluvial soil is the most fertile soil followed by black soil and red soil. While the laterite soil and desert soil are the least fertile.