Step 1: Match A) 2,4-D
\begin{itemize}
\item 2,4-D (2,4-Dichlorophenoxyacetic acid) is a synthetic auxin.
\item It is widely used as a selective herbicide, specifically designed to kill broadleaf (dicotyledonous) weeds without significantly harming monocot crops (like corn or wheat). It does this by causing uncontrolled growth.
\item So, A $\rightarrow$ IV. Dicotyledon weed killer.
\end{itemize}
Step 2: Match B) GA\textsubscript{3}
\begin{itemize}
\item GA\textsubscript{3} refers to Gibberellic acid, a prominent type of gibberellin, which is a plant hormone.
\item Gibberellins promote stem elongation, seed germination, and fruit development. In the Brewing Industry, gibberellins are applied to barley grains during malting to stimulate the rapid synthesis and activity of $\alpha$-amylase, an enzyme that breaks down starch into sugars fermentable by yeast.
\item So, B $\rightarrow$ I. Brewing Industry.
\end{itemize}
Step 3: Match C) Cytokinin
\begin{itemize}
\item Cytokinins are plant hormones known for promoting cell division and delaying senescence (aging) processes in plants.
\item A key function of cytokinins is to Delay of leaf senescence by mobilizing nutrients to the leaves and maintaining chlorophyll content.
\item So, C $\rightarrow$ III. Delay of leaf senescence.
\end{itemize}
Step 4: Match D) Ethylene
\begin{itemize}
\item Ethylene is a gaseous plant hormone primarily involved in fruit ripening, senescence, and abscission.
\item Many fruits exhibit a phenomenon called "respiratory climacteric" during ripening, which is a sharp increase in respiration rate often induced by ethylene.
\item So, D $\rightarrow$ II. Respiratory climactic.
\end{itemize}
Step 5: Formulate the complete match and check options
Based on the individual matches:
A $\rightarrow$ IV
B $\rightarrow$ I
C $\rightarrow$ III
D $\rightarrow$ II
Let's check this sequence with the given options:
% Option
(1) A-IV, B-I, C-III, D-II (Matches our derived sequence)
% Option
(2) A-IV, B-III, C-II, D-I (Incorrect)
% Option
(3) A-I, B-II, C-III, D-IV (Incorrect)
% Option
(4) A-I, B-III, C-II, D-IV (Incorrect)
Therefore, Option (1) is the correct answer.
