Which of the following statement regarding waveguides is incorrect?%!

• A. At waveguide can be coupled to a coaxial cable
• B. At frequencies below the cut off value the wave progresses across the waveguide after total reflections
• C. Waveguides are usually air filled hollow conducting metallic tubes for transmitting UHF and microwaves
• D. Waveguides can handle large power at UHF and microwaves