For interference of two light waves, it is necessary that their sources must be coherent, which means the waves have zero or constant phase difference. Also, the wave should be monochromatic, i.e. they must have the same wavelengths. If in Young's double-slit experiment, the source is white and it is covered with a red and blue filter, then both the waves will have different frequencies and wavelengths. So, there will be no interference. For the interference pattern to be formed on the screen, the sources should be coherent and emit lights of the same frequency and wavelength. In Young’s double-slit experiment, when one of the holes is covered by a red filter and another by a blue filter, in this case, due to filtration only red and blue lights are present. In YDSE monochromatic light is used for the formation of fringes on the screen. Hence, in this case, there shall be no interference fringes.
Hence, option (3) is the correct answer.