Two Small Identical Speakers Are Connected (In Phase)to the Same

Multiple Choice

Two small identical speakers are connected (in phase) to the same source.The speakers are 3 m apart and at ear level.An observer stands at X, 4 m in front of one speaker as shown.If the amplitudes are not changed, the sound he hears will be least intense if the wavelength is:

A) 1 m
B) 2 m
C) 3 m
D) 4 m
E) 5 m