Which of the following are crystalline solids?
NaCl, KCl, Diamond
NaCl, Rubber, Glass
Diamond, Plastic, NaCl
KNO3, Glass, Quartz
Crystalline solids have a regular arrangement of constituent particles but amorphous solids like glass, rubber, plastic have an irregular arrangement. So NaCl, KCl & Diamond are crystalline solids.
Option(a) is correct