Which of the following is an advantage of waveguide as a transmission line?

When evaluating the given options, it is important to distinguish between a simple characteristic and an actual 'advantage.' It is absolutely true that waveguides are expensive, heavy, difficult to install, and highly sensitive to frequency based on their physical dimensions. However, all of these are major disadvantages. The singular reason radio engineers and amateurs tolerate these significant drawbacks is because waveguides offer exceptionally low loss at microwave frequencies. At these extremely high frequencies, standard coaxial cables would suffer massive signal attenuation, making the low loss of a waveguide an invaluable advantage.