What's the easiest way to identify calcite

Although calcite reacts with HCl amazingly, this reaction is mainly used too identify limestone and dolostone in the field. my suggestion would be to use double refraction to identify calcite. By double refraction when light passes through calcite, it is split into two rays and is refracted twice. I would suggest to take a piece of paper and make a point with pencil, then place the calcite mineral on top of the point and see whether the point splits into two or not. If it does then it is calcite.

The best property to identify calcite is the acid test, since this mineral always produces effervescence with acids. It can be used as a criterion to know if the cement of sandstones and conglomerates is calcite.

a is the correct answer