[Calcium1808]

I have the following multiple choice question:
Which of the following statements best describes the characteristics of partition chromatography?
a) Ions in mobile phase are attracted to counterions covalently attached to stationary phase
b) Solute equillibrates between mobile phase and surface of stationary phase.
c) Solute in mobile phase is attracted to specific groups covalently attached to stationary phase.
d) Solute equillibrates between mobile phase and film of liquid attached to stationary phase.

I don't know whether it is b or d, since in partition chromatography the liquid stationary phase is bonded to a solid surface and the solute then equilibrates between the stationary phase and mobile phase, therefore for d, the liquid is not attached to the stationary phase, it is the stationary phase.
Appreciate your help.