JA induces defense against:
Herbivores and necrotrophs (C) is correct here. This is core Jasmonic acid: once you know the definition or pathway step, Herbivores and necrotrophs is the clear fit. The wrong ones are A) Biotrophic pathogens only; B) Abiotic stress only; D) Viruses only. If the topic is about gradients or potentials, water/solutes move from higher to lower of the relevant quantity.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.
