Which protein forms a complex with FT in the shoot apical meristem?
FD (C) is correct here. This is core PSS-Sec-E-Sensory biology: once you know the definition or pathway step, FD is the clear fit. The wrong ones are A) FLC; B) CO; D) FRI. If the topic is about gradients or potentials, water/solutes move from higher to lower of the relevant quantity.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.