During photomorphogenesis, HY5 protein levels are:
High (C) is correct here. This is core PHYTOCHROME: once you know the definition or pathway step, High is the clear fit. The wrong ones are A) Low; B) Absent; D) Unchanged. 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.