The modes in a rectangular waveguide are denoted by TMmn/TEmn where m and n are the eigen numbers along the larger and smaller dimensions of the waveguide respectively. Which one of the following statements is TRUE?
A. The TM10 mode of the waveguide does not exist
B. The TE10 mode of the waveguide does not exist
C. The TM10 and the TE10 modes both exist and have the same cut-off frequencies
D. The TM10 and the TM01 modes both exist and have the same cut-off frequencies