Due to the Doppler effect, waves from an approaching source (moving toward the observer) are observed as having a shorter wavelength than when they were emitted. Which of the following pairs could represent the kind of radiation emitted from a source rapidly approaching Earth and the kind of radiation it is detected as on Earth? A
emitted as a gamma ray, observed as ultraviolet light

B
emitted as a microwave, observed as a radio wave

C
emitted as yellow light, observed as blue light

D
emitted as ultraviolet light, observed as infrared radiation