A System in Which the Light Intensity of the Wavelength

A system in which the light intensity of the wavelength produced by each atom is directly proportional to the number of atoms emitting energy, which in turn is directly related to the concentration of the compound being measured, describes:
1) atomic absorption spectrophotometry
2) atomic emission flame photometry
3) UV/Visible spectrophotometry
4) fluorometry

A) 1, 2, 3, 4
B) 1, 2, 3
C) 1, 3
D) 2, 4