In YDSE, coherent monochromatic light having wavelength 600 nm falls on the slits. First-order bright fringe is at 4.84 mm from central maxima. Determine the wavelength for which the first-order dark fringe will be observed at the same location on screen. (Take D=3 m.)
(1) 600 nm
(2) 1200 nm
(3) 300 nm
(4) 900 nm