the age of the soil particles the size of the soil particles the color of the soil particles the luster of the soil particles
I gave my students this multiple choice question: Which of the following has the greatest effect on the ability of soil to hold water?

Only one answer is correct among these 4 choices:
- the age of the soil particles
- the size of the soil particles
- the color of the soil particles
- the luster of the soil particles

Could you tell me which one is correct?

the size of the soil particles