Which three statements are true about tunnels?

Which three statements are true about tunnels? (Choose three.)

A.
By default, GRE tunnels copy theToS bits of the inner packet’s IP header to the GRE header.

B.
By default, GRE allows fragmentation of packets traversing nodes whose MTU is lower than the de-encapsulating devices.

C.
IP-IP tunnels transport only IP traffic.

D.
GRE and IP-IP tunnels are configured by defining a logical unit for a tunnel interface.

E.
GRE encapsulations and IP-IP encapsulations both add additional overhead to a packet.