You are trying to determine the wavelength of a particular line of a sample's emission spectrum using a diffraction grating. Unfortunately, the slit spacing has worn off of the grating and you do not have any way to measure that directly. You do, however, have a green laser pointer that has a labeled wavelength of 532 nm. When you shine the laser pointer and the sample's emission spectrum directly on the grating at the same time, you notice that the fourth peak for the unknown wavelength exactly corresponds with the fifth peak of the laser pointer on each side of the pattern. What is the unknown light's wavelength?
a. 665 nm
b. 426 nm
c. 435 nm
d. 650 nm
e. 2660 nm
show work.