[单选题]
Light of wavelength 580 nm is incidev:nvq h/5,8: . +.rakglut7,s g mtdjnvmke*int on a slit of width 0.300 mm. i4fs: c.sac6z;wi )te An observing screen is placed 2.0cfwa isc 4zt i;6e.s:)0 m from the slit. Find the width of the central maximum.
A. $0.26 \; mm$
B. $1.9 \; mm$
C. $3.9 \; mm$
D. $7.7 \; mm$