When a hostname is configured through the cisco cli, which three naming conventions are part of the guidelines?

When a hostname is configured through the Cisco CLI,  some naming conventions must be follows.
These naming conventions are as follows:
1- The name of the host must always begin with a letter
2- The name of the host cannot contain any spaces
3- The length of the hostname should always be less than 64 letters

Ibelieve its b but u might have to

Centriole.centrioles are present in animal cells but are usually absent in plant cells.