Answer: A) calcite
Explanation:
Hardness can be defined as the ability of the mineral to resist the scratch. It is the property to judge the hardness of the mineral. Mineralogist study this property of hardness using Mohs hardness scale.
Talc is the least hard substance after that gypsum, then calcite, fluorite, and then apatite.
The gypsum can be scratched by the calcite but the calcite cannot scratch apatite as it is softer than apatite.