pF value of hygroscopic coefficient is:

Correct option is A

The  hygroscopic coefficient of soil, which is the amount of moisture remaining in the soil after it has been dried to a constant weight in an oven, corresponds to a  pF value of 4.5. This value indicates the soil’s ability to retain water against evaporation and is a measure of the soil’s moisture content under hygroscopic conditions.
Examine each option:
(a) 4.5: Correct answer; represents the pF value for hygroscopic coefficient.
(b) 7.0: Higher than the pF value for hygroscopic coefficient.
(c) 7.5: Higher than the pF value for hygroscopic coefficient.
(d) 2.3: Represents a different soil moisture tension.
(e) 1.5: Represents a different soil moisture tension.