Water moves from one region to another along:
C fits best: Water potential gradient. Keep the WATER POTENTIAL basics straight and Water potential gradient stands out as the precise answer. Avoid: A) Osmotic gradient; B) Pressure gradient; D) Diffusion pressure. 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.