Question $5$

An engineer makes a decision to utilize WR$-90$ to carry signals at a frequency of $7\mathrm{.}2$ GHz $.$ Note that this frequency is somewhat below the recommended frequency range of the waveguide. Which comment below is the best one regarding this engineer's decision.

This decision is catastrophic because the waveguide will be cutoff and no signal propagation will occur.

This decision is brilliant! There is no good reason for the recommended frequency range starting at $8\mathrm{.}2$ GHz$.$

This decision is not catastrophic but may result in greater than desired signal attenuation due to excessive conductor loss at frequencies close to the cutoff frequency of the waveguide.

It would be best to re$-$design the entire system for a carrier frequency higher than $7\mathrm{.}2$ GHz $.$