ANS:D - all 'a', 'b' & 'c'.

The rate of solid-liquid extraction can be limited by all of the following:

1. Phase Change of the Solute:
   • The phase change of the solute as it dissolves in the solvent can impact the extraction rate. This involves the transition of the solute from a solid phase to a dissolved phase in the solvent. Depending on the solute's properties, this phase change may occur at a certain rate, affecting the overall extraction process.
2. Diffusion of the Solute Through the Solvent in the Pores to the Outside of the Particle:
   • After the solute dissolves in the solvent, it needs to diffuse through the solvent to reach the exterior surface of the solid particle. This process can be limited by factors such as the size of the pores, the viscosity of the solvent, and the concentration gradient between the inside and outside of the particle.
3. Diffusion of the Solute from the Solution in Contact with the Particle to the Main Bulk of the Solution:
   • Once the solute reaches the exterior surface of the solid particle, it must further diffuse into the bulk of the solution. This process can also be influenced by factors such as concentration gradients, molecular interactions, and the properties of the solvent and solute.

Therefore, the rate of solid-liquid extraction can indeed be limited by all three factors: the phase change of the solute, the diffusion of the solute through the solvent in the pores to the outside of the particle, and the diffusion of the solute from the solution in contact with the particle to the main bulk of the solution.