To solve this problem, we need to match the elements in List I with their corresponding roles in List II. Let's analyze each element:$\newline \bullet$A. Iron:$\newline$ - Iron is known to be an activator of catalase, an enzyme that helps in the breakdown of hydrogen peroxide.$\newline$ - This matches with III.$\newline \bullet$B. Zinc:$\newline$ - Zinc plays a crucial role in the synthesis of auxin, a plant hormone that regulates growth.$\newline$ - This matches with I.$\newline \bullet$C. Boron:$\newline$ - Boron is essential for cell elongation and differentiation in plants.$\newline$ - This matches with IV.$\newline \bullet$D. Molybdenum:$\newline$ - Molybdenum is a component of nitrate reductase, an enzyme involved in nitrogen metabolism.$\newline$ - This matches with II.$\newline$Now, let's match the items from List I with List II:$\newline A \rightarrow III, B \rightarrow I, C \rightarrow IV, D \rightarrow II \newline$This corresponds to Option 3.