Two monochromatic coherent sources of wavelength 5000 A are placed along line normal to screen as shown. Find the order of central bright fringe if $d = 0.5mm$ and $D = 1m$

Question

(A) 500 $\qquad$ (B) 4000 $\qquad$ (C) 1000 $\qquad$ (D) 2000