4. A circle touches a g8iven straight line and cuts off a constant length 2d from another straight line perpendicular to the first straight line. The locus of the centre of the circle is
(a) Hyperbola
(b) Circle
(c) Parabola
(d) Pair of perpendicular lines
[The two straight lines to be considered as coordinate axes]
4. A circle touches a g8iven straight line and cuts off a constant length 2d from another straight line perpendicular to the first straight line. The locus of the centre of the circle is
(a) Hyperbola
(b) Circle
(c) Parabola
(d) Pair of perpendicular lines
[The two straight lines to be considered as coordinate axes]