Answer: Option A) Yield would decrease, but purity would not be affected.
Explanation:
Sufficient grinding of the two initial reactants will provide a wider surface area for the reactants particles to combine more rapidly, forming products that still retain the purity.
On the other hand, when reactants are not properly grinded the yield of products decrease due to lesser surface area between reactants particles, while the purity of product formed is unaffected.
Thus, the answer is option A