Consider a Single-Slit Diffraction Pattern Caused by a Slit of Width

Consider a single-slit diffraction pattern caused by a slit of width a.There is a minimum at sin(\theta\) equal to:

A) exactly $\lambda$ /a
B) slightly more than $\lambda$ /a
C) slightly less than $\lambda$ /a
D) exactly $\lambda$ /2a
E) very nearly $\lambda$ /2a