Assertion $\left(\mathrm{A}\right):$ The foolish seedling disease in rice seedlings is caused by a fungal pathogen, Gibberella fuzikuroi.

Reason $\left(\mathrm{R}\right):$ E. Kurosawa reported the appearance of symptoms of the disease in uninfected rice seedlings when they were treated with sterile filtrates of the fungus and the active principle was identified as gibberellic acid.

The correct answer is: