The answer is YES. Indeed, consider a metrics $\ \rho_A\ $ in A, topologically equivalent to the induced topology from $\ (X\ d),\ $ and such that $\ (A\ \rho_A)\ $ is isometric to the standard unit interval $\ [0;1]\ $ with the euclidean distance. Thus there is a function $\ f:[0;1]\rightarrow A,\ $ such that $$ \forall_{t\in[0;1]}\quad\rho_A(v\ \,f(t))\ \ =\ \ t$$ Hausdorff theorem provides a metrics $\ \rho\ $ in $\ X,\ $ topologically equivalent to $\ d,\ $ and such that $ \rho|A\times A\ =\ \rho_A.\ $ Thus a required retraction $\ r: X\rightarrow A\ $ can be given as follows: $$\forall_{p\in X}\quad r(p)\ :=\ f(\rho(v\ p))$$ Done, that's it. <hr> **REMARK** @Pedro carefully singled out the end-points of an arc. For other points of the arc the required retraction in general doesn't exist (which had to be obvious to Pedro). Indeed, consider a circle $\ S,\ $ and let a closed semicircle $\ A\ $ serve as the arc in $\ S.\ $ Then for every retraction $\ r : S\rightarrow A,\ $ and for every point $\ x\in A\ $ different from either of the end-points of $\ A,\ $ the inverse $\ r^{-1}(x)\ $ consists of more than one point.