Water potential in plant system can never be:
Correct option is C, Positive. In WATER POTENTIAL problems like this, the accurate statement is Positive; the others are common mix-ups. Not these: A) Negative; B) Zero; D) Low. Tissue transport questions usually turn on xylem vs phloem, living vs dead cells, or source vs sink.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.