Correct option is B
✅ (b) Ethylene: • Banana is a climacteric fruit, and its ripening is triggered by a sudden surge in ethylene. • Ethylene induces enzyme activity that softens fruit, converts starch to sugar, and develops aroma.
❌ (a) Auxin, (c) G.A., (d) Cytokinine: • These are growth regulators involved in growth and development, not ripening.