Calcium deficiency primarily affects:
B fits best: Young meristems. Keep the MINERAL Transport basics straight and Young meristems stands out as the precise answer. Avoid: A) Older leaves; C) Mature leaves; D) Seeds. 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.