Let the man starts from point S and moves 9 km South to reach T and then turns to East and goes 3 km. He turns South and walks 3 km to point V and then moves 8 km towards West to finally stop at point W.
=> $$(SW)^2=(SX)^2+(XW)^2$$ => $$(SW)^2=(9+3)^2+(8-3)^2$$
=> $$(SW)^2=144+25=169$$ => $$SW=sqrt{169}=13$$ km
$$ herefore$$ He is 13 km from the starting point.
=> Ans - (D)