What are the advantages of using a solvent pair for recrystallization? select all that apply.

a you can control the solubility of the substance in the mixed solvent.

b you don't have to know the exact amounts of the solvents needed.

c you can quickly make the solution supersaturated by adding more of the solvent with less dissolving power.

d you can quickly make the solution supersaturated by adding more of the solvent with greater dissolving power.

e you can calculate the precise amounts of the solvent needed for recrystallization.

i chose b and e but got it wrong. i'm not sure if it's because i chose the wrong ones, or i didn't choose all of the correct answers.

i've looked through my notes and textbooks many times, but i'm still a bit confused about this. please help!?