Which F‑box protein mediates degradation of AUX/IAA repressors?
C fits best: TIR1. Keep the Phytohormone ALL basics straight and TIR1 stands out as the precise answer. Avoid: A) COI1; B) SLY1; D) EBF1. Light and flowering items often hinge on which photoreceptor or day-length rule is in play.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.