Which statement is correct regarding the default MPLS TTL behavior?

A.
When an ingress edge LSR receives an IP packet, it will decrement the IP TTL field by 1; then it
will set the MPLS Label TTL field to 255.

B.
When an ingress edge LSR receives an IP packet, it will decrement the IP TTL field by 1; then it
will copy the decremented IP TTL field into the MPLS Label TTL field.

C.
When an ingress edge LSR receives an IP packet, it will just copy the IP TTL field into the
MPLS Label TTL field.

D.
When an ingress edge LSR receives an IP packet, it will copy the IP TTL field into the MPLS
Label TTL field first; then it will only decrement the MPLS Label TTL field by 1.

E.
When an ingress edge LSR receives an IP packet, it will copy the IP TTL field into the MPLS
Label TTL field first; then it will only decrement the IP TTL field by 1.

Explanation: