Why do fluorescence spectrometers often use double-beam optics?

Question: Why do fluorescence spectrometers often use double-beam optics?
[A].

So a reference solution can be used

[B].

To compensate for beam attenuation by the monochromator

[C].

To compensate for power fluctuations in the radiation source

[D].

All of the above

Answer: Option C

Explanation:

No answer description available for this question.