I think that the answer is 4, but i dont know
A non-sandblasted rock could be rough or smooth depending on how it was formed.
A sandblasted rock should be much smoother, since the sand blasts away any rough edges. It will, however, be slightly smaller due to losing those edges.
Example of solid - solid homogeneous mixture is copper metal - silver metal like coins and alloys.
Homogeneous mixture is a mixture in which one of the substances often changes in form as in a solution of sugar in water. It contains variable proportions. Solution can contain two substances, three substances or more, in a single physical state. The component of a solution that is present in greatest quantity is usually called the solvent and all other components are called solutes.