Needs["PlotLegends`"]
ListLinePlot[Table[n^(1/p), {p, 4}, {n, 10}],
PlotMarkers -> Automatic, GridLines -> {None, Automatic},
AxesOrigin -> {0, 0}, PlotRange -> {{0, 12}, {0, 12}},
PlotLegend -> {"A", "B", "C", "D"}, LegendPosition -> {-0.5, 0.5},
FrameLabel -> {"x", "y"}, Frame -> {{True, False}, {True, False}},
ImageSize -> 600, ShadowOffset -> 0, LegendBorder -> None,
LegendOrientation -> Horizontal, LegendBorderSpace -> 0]
