Answer :
Answer:
C.
Try to scratch the marble with each of the minerals, and group the minerals that do scratch the marble together.
Explanation:
A fair test would be to try scratching the marble with each of the minerals in her group and see the outcome.
The ones that scratch the other is harder and scratched one is less hard.
Since marble is known, any mineral that scratches it is harder and those ones that do not scratch it are less harder.
The moh's scale of hardness gives us good clue into the hardness of mineral with Talc being the least hard and diamond the hardest of all.