[单选题]
Light of wavelength 575 nm falls on a double-slit and thpmdkvv j5,i8+ e third orqmb:2/zprz0rsr7/: i-lvm yl cx( ad* e)uu7 bder bright fringe 2m(*0es -zu bb:rd/7ui)m z lr/7ypl vq:xrcais seen at an angle of $6.5^{\circ}$. What is the separation between the double slits?
A. $5.0 \; mm$
B. $10 \; mm$
C. $15 \; mm$
D. $20 \; mm$