Line Waves with Wavelength $\lambda$ Going Through a Slit with Width a Will Be Diffracted

Multiple Choice

Line waves with wavelength $\lambda$ going through a slit with width a will be diffracted into circular waves with approximately equal amplitude in all forward directions

A) Always
B) Never
C) Only if $\lambda \gg>a$
D) Only if $a>>\lambda$
E) Only if $a=\lambda$