[" Frive tangents drawn from a point P to the parabola "y^(2)=4x" are at right angles,then the locus of is "],[[" (i) "2x+1=0," (B) "x=-1," (C) "2x-1=0," (D) "x=1],[" The tangent PT and the normal PN to the parabola "y^(2)=4ax" at a point Pon it meation in "]]