Which of the following is not true about crystalline solids

Solids are defined by an extended three-dimensional arrangement of atoms, ions, or molecules that are generally locked into their positions. The components can be arranged in a regular repeating three-dimensional array (a crystal lattice) to form a crystalline solid, or they can be arranged more or less randomly to form an amorphous solid. Crystalline solids have sharp melting points, well-defined edges, and faces, and diffract x-rays. Amorphous solids, on the other hand, have irregular or curved surfaces, do not produce well-resolved x-ray diffraction patterns, and melt at a wide range of temperatures.

Hence, the required answer is option C).