Match the Plant Growth Regulator (PGR) with its chemical nature.
| Column I | Column II |
|---|---|
| (a) Auxin (IAA) | (i) Derivatives of carotenoids |
| (b) Gibberellin (GA₃) | (ii) Adenine derivatives (N⁶-furfurylaminopurine) |
| (c) Cytokinin (Kinetin) | (iii) Indole compounds |
| (d) Abscisic acid (ABA) | (iv) A terpene compound |