A.
Plot3D[x^2-y^2,{x,-3,3},{y,-3,3}, PlotStyle → Opacity[0.2],BoxRatios → {1,1,1}]
B.
Plot3D[x^2-y^2,{x,-3,3},{y,-3,3}, BoxRatios → {1,1,1},PlotStyle → Opacity[0.3]]
C.
Plot3D[x^2-y^2,{x,-3,3},{y,-3,3}, PlotStyle → Opacity[1.0],BoxRatios → {1,1,1}]
D.
Plot3D[x^2-y^2,{x,-3,3},{y,-3,3},BoxRatios → {1,1,1}, PlotStyle → Opacity[0.25]]