Intermediary companion cells are characterized by:
C fits best: Numerous plasmodesmata. Keep the PHLOEM TRANSLOCATION basics straight and Numerous plasmodesmata stands out as the precise answer. Avoid: A) Few plasmodesmata; B) No chloroplasts; D) Thick lignified walls. 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.