Correct option is Ad(f(x),f(y))≤d(x,y), ∀ x,y∈X. is given ⟹ ∀ ϵ>0, ∃ δ>0 for any c∈X such that d(f(x),f(c))<ϵ whenever d(x,c)<δ.Thus, f(x) is a continuous function.d(f(x), f(y)) \leq d(x, y), \; \forall \, x, y \in X.\ \text{is given}\\\implies \forall \, \epsilon > 0, \, \exists \, \delta >0 \text{ for any } c \in X \text{ such that }\\d(f(x), f(c)) < \epsilon \; \text{whenever} \; d(x, c) < \delta.\\\text{Thus, } f(x) \text{ is a continuous function.}d(f(x),f(y))≤d(x,y),∀x,y∈X. is given⟹∀ϵ>0,∃δ>0 for any c∈X such that d(f(x),f(c))<ϵwheneverd(x,c)<δ.Thus, f(x) is a continuous function.