Correct option is B
Given:ρ={(a,b)∈Z×Z∣∣a−b∣≤5}Check Reflexive:∣a−a∣=0≤5=>(a,a)∈ρ(Always true)=>ρ is reflexiveCheck Symmetric:∣a−b∣≤5=>∣b−a∣=∣a−b∣≤5=>(b,a)∈ρ=>ρ is symmetricCheck Transitive:Let a=1,b=5,c=10∣a−b∣=4,∣b−c∣=5=>(a,b),(b,c)∈ρ∣a−c∣=9≰5=>(a,c)∈/ρ=>ρ is not transitiveAnswer: (B) Reflexive and Symmetric