Xylem in vascular plants is characterized by presence of which conducting elements?
Tracheary elements (C) is correct here. This is core PSS- Sec-F-Transport: once you know the definition or pathway step, Tracheary elements is the clear fit. The wrong ones are A) Sieve tubes; B) Companion cells; D) Parenchyma cells. 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.