A Planar Cross Section Through Two Spherical Waves Emanating from the Sources

A planar cross section through two spherical waves emanating from the sources S₁ and S₂ in the plane is shown in the figure.S₁ and S₂ are in phase.The black circles are one and two wavelengths from their respective sources.The lighter circles are one half and one and a half wavelengths distant from their respective sources.If the waves shown arriving at P₁ both arrive with amplitude A,the resultant amplitude at point P₁ is

A) 0.
B) .
C) A.
D) .
E) 2A.