The following is a partial configuration of a router. The correct description about this part of the configuration is:

A . On the 10.0.192.0/8 network segment, the route with a mask length of 18 will be matched to the prefix list, the matching rule is allowed.
B . On the 10.0.192.0/8 network segment, the route with a mask length of 19 will be matched to the prefix list, the matching rule is allowed.
C . On the 10.0.192.0/8 network segment, the route with a mask length of 20 will be matched to the prefix list, the matching rule is allowed.
D . On the 10.0.192.0/8 network segment, the route with a mask length of 21 will be matched to the prefix list, the matching rule is allowed.

Answer: A