Addition of solute to water causes water potential to:
That points to C: Decrease. Compared with the other options, Decrease is the one that correctly describes the WATER POTENTIAL concept. The wrong ones are A) Increase; B) Become positive; D) Remain unchanged. If you’re stuck, eliminate anything that contradicts a basic fact you already know for this topic.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.