Answer:
c.attenuation
Step-by-step explanation:
In telecommunication, it is called attenuation of a signal, be it acoustic, electrical or optical, to the loss of power suffered by it when passing through any transmission medium.
Attenuation is usually not expressed as a difference in powers but in logarithmic units such as decibels, which are more comfortable to use when calculating.
The attenuation is expressed in decibels (db) and the power is measured with this formula:
α = 10 * log (P1 / P2)
where P is the power both initial and final.