What is the main difference between a VARIABLE length subnet mask and a FIXED subnet mask?

Question $2$ options:

Fixed subnets set the maximum number of hosts in a pre$-$defined pattern or standard.

Variable length allows a user to modify the maximum number of hosts based on the number of subnets needed. This thereby limits the number of total possible hosts and conserves the remaining hosts to be used at a later time.

Both statements are true.

Both statements are false.