Light of Wavelength $\lambda$ Is Normally Incident on Some Plane Optical Device

Multiple Choice

Light of wavelength $\lambda$ is normally incident on some plane optical device. The intensity pattern shown is observed on a distant screen ( $\theta$ is the angle measured to the normal of the device) . The device could be:

A) a single slit of width W
B) a single slit of width 2W
C) two narrow slits with separation W
D) two narrow slits with separation 2W
E) a diffraction grating with slit separation W