Green light reverses blue-light-induced stomatal opening through:
Pick C: Zeaxanthin. Thinking through STOMATA MOVEMENT step by step rules out the lookalikes and leaves Zeaxanthin. Skip these: A) Phototropins; B) Phytochromes; D) Cryptochromes. For hormones and genes, match the molecule or gene to its real role, not a neighboring pathway.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.