Which statement correctly describes the disabling of IP TTL propagation in an MPLS network？（）

• A、The TTL field from the IP packet is copied into the TTL field of the MPLS label header at the ingress edge LSR
• B、TTL propagation cannot be disabled in an MPLS domain
• C、TTL propagation is only disabled on the ingress edge LSR
• D、The TTL field of the MPLS label header is set to 255
• E、The TTL field of the IP packet is set to 0