Exposure of etiolated seedlings to light results in:
B fits best: De-etiolation. Keep the PHYTOCHROME basics straight and De-etiolation stands out as the precise answer. Avoid: A) Skotomorphogenesis; C) Dormancy; D) Vernalization. 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.