Mohs scale is used to determine the hardness of a material or substance.
This scale includes ten materials and each of them are placed according to their hardness from bottom to top as follows.
Talc = 1
Gypsum = 2
Calcite = 3
Fluorite = 4
Apatite = 5
Orthoclase = 6
Quartz = 7
Topaz = 8
Corundum = 9
Diamond = 10
Greater is the number, the hardest will be the substance, that is, according to Mohs scale diamond is the hardest substance and talc is the least hardest substance.
Thus, we can conclude that option (c) is the correct answer.