Explanation:
Given elements are:Ce, Eu, Ho, NWe have to find the correct order of atomic radii.Cerium (Ce), europium (Eu) and Holmium (Ho) are lanthanide elements. Their metallic radius is:Ce = 181.8 pmEu = 208.4 pmHo = 176.2 pmAtomic radius of nitrogen (N) = 65 pmThus, the atomic radii follow the order:Eu > Ce > Ho > N. Hence, the correct option is (C).