[单选题]
Light of wavelength 4t 7c 8wcxlk id2lfs-ir.4 ;z2g3qknz jfnre4j5v:o:ejq. wuu vf0z./ i/v ) e$λ_1$ and $λ_2$ is incident on a diffraction grating with the slit spacing of $d$. A series of bright lines are formed on a screen.
What is the ratio $\frac{sinθ_1}{sinθ_2}$ ?
A. $\frac{2λ_1}{λ_2}$
B. $\frac{2λ_2}{λ_1}$
C. $\frac{λ_1}{2λ_2}$
D. $\frac{λ_2}{2λ_1}$
