The Pfr form of phytochrome absorbs maximally at approximately:
Pick D: 730 nm. Thinking through PHYTOCHROME step by step rules out the lookalikes and leaves 730 nm. Skip these: A) 450 nm; B) 550 nm; C) 660 nm. 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.