To solve this problem, we need to match the items in Column I with the appropriate descriptions in Column II. Let's analyze each item:$\newline \bullet$a. Organ of Corti:$\newline$ - The Organ of Corti is located on the basilar membrane within the cochlea of the inner ear.$\newline$ - This matches with iv.$\newline \bullet$b. Cochlea:$\newline$ - The cochlea is a coiled part of the labyrinth in the inner ear.$\newline$