GLABRA2 acts:
B fits best: Downstream of GL1–GL3–TTG1. Keep the Jasmonic acid basics straight and Downstream of GL1–GL3–TTG1 stands out as the precise answer. Avoid: A) Upstream of GL1; C) As JA receptor; D) As JAZ protein. 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.