A green laser beam of wavelength 540 nm passes through a pinhole and illuminates a dartboard 3.0 m past the pinhole. The first minimum in the intensity coincides with the ring surrounding the bull's-eye, 12 mm in diameter. What is the diameter of the pinhole?

A. 0.14 mm 

B. 0.33 mm 

C. 0.59 mm 

D. 1.2 mm