Hydraulic conductivity is highest in:
C fits best: Sandy soil. Keep the WATER TRANSPORT basics straight and Sandy soil stands out as the precise answer. Avoid: A) Clay soil; B) Silt soil; D) Peaty soil. Light and flowering items often hinge on which photoreceptor or day-length rule is in play.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.