The correct option is D GA
Foolish seedling disease or Bakanae disease is a disease of rice seedlings, which was caused by a fungal pathogen Gibberella fujikuroi. Diseased plants are often conspicuous in a field because of their extreme height and pale, spindly appearance.
E. Kurosawa reported the appearance of symptoms of the disease in uninfected rice seedlings when they were treated with sterile filtrates of the fungus. The active substances were later identified as gibberellic acid (GA).