To prepare crust, combine crumbs, margarine, and sugar in a mixing bowl. Press mixture firmly in a 9" pie pan. Chill one hour, or until firm. Or, bake in a 375 oven for ten minutes or until edges are brown. Cool on rack before filling. Placed sliced bananas onto bottom of crust; set aside. Meanwhile, prepare pudding mix according to package directions, using 1 3/4 cups milk. Mix until well blended. Fold in marshmallows and whipped topping. Pour mixture over bananas. Chill several hours or overnight.