by noticing if they dissolve in water by studying the color of the substance by observing if they stick to a surface by examining the shape of the crystal
I gave my students this multiple choice question: A group of students is investigating two substances to determine which is table salt and which is table sugar. How would the students best identify each substance?

Only one answer is correct among these 4 choices:
- by noticing if they dissolve in water
- by studying the color of the substance
- by observing if they stick to a surface
- by examining the shape of the crystal

Could you tell me which one is correct?

by examining the shape of the crystal