550 nm light through a single slit has an angular width of 15°. What is the width of the slit?
a 4.0 x 10⁻⁶m
b 2.1 x 10⁻⁶m
c 3.4 x 10⁻⁶m
d 5.0 x 10⁻⁶m
e 4.2 x 10⁻⁶m