Water potential of saline soil is mainly affected by:
Ψs (C) is correct here. This is core WATER POTENTIAL: once you know the definition or pathway step, Ψs is the clear fit. The wrong ones are A) Ψp; B) Ψg; D) Ψm. 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.