Concept:X-rays are used to study the internal arrangement of particles in crystalline giant molecules.Explanation:The arrangement of atoms or particles in giant molecules and crystals is studied by X-ray crystallography.X-rays have wavelengths comparable to the distances between particles, so they are diffracted by the crystal lattice, revealing the arrangement.Gamma rays, alpha particles, and beta particles are not suitable for this structural analysis.Answer:C. X-rays