The phase difference between light waves from two slits in Young's double slit experiment is $\pi$. Will the central fringe be bright or dark?

Q. In Young's double slit experiment, the phase difference between the light waves reaching third bright fringe from the central fringe will be ($\lambda =6000\mathring{A}$)

Q. In Young's double slit experiment ,wavelength of light is $6000\mathring{A}$ The the phase difference between the light waves reaching the third bright fringe from the central fringe will be:

Q. In Young's double slit experiment, the phase difference between the waves reaching the central fringe and third bright fringe will be

Q. In Young's double slit experiment the phase difference between the waves reaching the central fringe and fourth dark fringe will be

Q. In the Young's double slit experiment, if the phase of each light wave coming from the two slits is changed by $\pi$, the fringe pattern will: