The Figure Shows Two Point Sources of Light,A and B,that

The figure shows two point sources of light,A and B,that emit light waves in phase with each other.A is distant 3λ from point P.B is distant 5λ from P.(λ is the wavelength. ) The phase difference between the waves arriving at P from A and B is

A) 0 rad.
B) π rad.
C) 2π rad.
D) 3π rad.
E) 4π rad.