In a Young's double slit set-up, light from a laser source falls on a pair of very narrow slits separated by 1.0 micrometer and bright fringes separated by 1.0 millimeter are observed on a distant screen. If the frequency of the laser light is doubled, what will be the separation of the bright fringes ?
(A) 0.25 mm
(B) 0.5 mm
(C) 1.0 mm
(D) 2.0 mm