Which of the following is a growth promoter?

Correct option is A

✅ (a) Auxin: • Auxins (e.g., IAA) are plant hormones that promote cell elongation, root formation, and apical dominance. • Widely used in rooting powders and tissue culture.
❌ (b) Ethylene: • It is a growth inhibitor involved in fruit ripening, leaf abscission, and senescence.
❌ (c) Carbonate: • Not a hormone, and has no role in plant growth promotion.