Which of the following is not a true statement about municipal bonds $($munis$)$ and corporate bonds?

Interest paid on munis is tax$-$exempt, while interest paid on corporate bonds is not.

Munis often have a range of maturities $($are serial issues$)$ but many corporate bonds do not.

Unlike corporate bonds, munis are rated by bond$-$rating agencies such as Moody's.

All of the above are differences between munis and corporate bonds.