To solve this problem, we need to determine which plant hormone can prevent fruit and leaf drop at early stages. Let's analyze each option:$\newline \bullet$Ethylene:$\newline$ - Ethylene is a plant hormone that promotes fruit ripening and leaf abscission.$\newline$ - It is not used to prevent fruit and leaf drop; rather, it accelerates these processes.$\newline \bullet$Auxins:$\newline$ - Auxins are plant hormones that promote cell elongation and are involved in various growth processes.$\newline$ - They are known to prevent premature fruit and leaf drop by maintaining the attachment of leaves and fruits to the plant.$\newline$ - Therefore, auxins are used to prevent early fruit and leaf drop.$\newline \bullet$Gibberellic acid:$\newline$ - Gibberellic acid is a plant hormone that promotes stem elongation, seed germination, and flowering.$\newline$ - It is not primarily used to prevent fruit and leaf drop.$\newline \bullet$Cytokinins:$\newline$ - Cytokinins are plant hormones that promote cell division and delay leaf senescence.$\newline$ - While they have various roles in plant growth, they are not specifically used to prevent fruit and leaf drop.$\newline$Based on this analysis, the correct option is:$\newline$Option 2: Auxins.