Step 1: Understanding the Concept:
This question requires matching specific horticultural applications with the Plant Bioregulator (PBR) or chemical used to achieve them.
Step 2: Detailed Explanation:
Let's match each application to the chemical:
\[\begin{array}{rl} \bullet & \text{(A) Rooting of cuttings: The induction of adventitious roots in cuttings is a primary function of auxins. (III) IBA (Indole-3-butyric acid) is the most widely used commercial auxin for this purpose. } \\ \bullet & \text{(B) Seed scarification: This process involves breaking, scratching, or softening the hard seed coat to allow water absorption and germination. A common method is chemical scarification using a strong (I) Acid treatment (like concentrated sulfuric acid). } \\ \bullet & \text{(C) Parthenocarpy in Mango: Parthenocarpy is the development of fruit without fertilization. While not a standard commercial practice in mango, combinations of growth regulators like (II) BA (a cytokinin) + Beta NOA (an auxin) can be used experimentally to improve fruit set and induce parthenocarpy. } \\ \bullet & \text{(D) Induction of flowering in Pineapple: Uniform flowering in pineapple is commercially induced by applying a substance that triggers it. (IV) Ethephon is commonly used, as it releases ethylene gas, which is the direct stimulus for flowering in pineapple. } \\ \end{array}\]
The correct matching is: A \(\rightarrow\) III, B \(\rightarrow\) I, C \(\rightarrow\) II, D \(\rightarrow\) IV.
Step 3: Final Answer:
The correct set of matches corresponds to option 2.