The correct answer is (A): Both assertion (a) and reason (r) are true, and reason (r) correctly explains assertion (a).
Leaching is a cooking technique where vegetables are soaked or boiled in water to remove excess soluble minerals. This process is particularly recommended for people with chronic kidney disease because their kidneys cannot efficiently eliminate potassium and phosphorus from the body. Since high levels of these minerals can be harmful in such patients, leaching helps reduce their content in vegetables, making them safer for consumption.