Light from a source emitting two wavelengths λ1 and λ2 is allowed to fall on Young's double-slit apparatus after filtering one of the wavelengths. The position of interference maxima is noted. When the filter is removed both the wavelengths are incident and it is found that maximum intensity is produced where the fourth maxima occurred previously. If the other wavelength is filtered, at the same location the third maxima is found. What is the ratio of wavelengths?
(1) 32
(2) 23
(3) 43
(4) 34