The Yellow Line of a Sodium Lamp Is Two Lines $\lambda$

Multiple Choice

The yellow line of a Sodium lamp is two lines very close together at $\lambda$ ₁ = 589.592 nm and $\lambda$ ₂ = 588.995 nm.If a diffraction grating has to resolve the first order diffraction lines by an angular separation of 0.1 ^$\circ$ ,what is the least number of lines per cm for the diffraction grating?

A) 12,400 cm^-1
B) 13,600 cm^-1
C) 14,700 cm^-1
D) 15,300 cm^-1
E) 16,700 cm^-1