The first enzymatic step of JA biosynthesis occurs in:
C fits best: Chloroplast. Keep the Jasmonic acid basics straight and Chloroplast stands out as the precise answer. Avoid: A) Cytosol; B) Peroxisome; D) Nucleus. 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.