Two Sources of Light Illuminate a Double Slit Simultaneously

Multiple Choice

Two sources of light illuminate a double slit simultaneously.One has wavelength 570 nm and the second has an unknown wavelength.The bright fringe of the unknown wavelength overlaps the bright fringe of the light of 570 nm wavelength.What is the unknown wavelength?

A) 456 nm
B) 326 nm
C) 380 nm
D) 713 nm