Negative pressure potential in xylem is known as:
Tension (C) is correct here. This is core WATER POTENTIAL: once you know the definition or pathway step, Tension is the clear fit. The wrong ones are A) Turgor; B) Osmosis; D) Diffusion. 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.