问题：

[单选] In MPLS networks, what s the benefit of disabling TTL propagation?（）

A . To provide a visible extension of MPLS TTL functionality in a non MPLS-enabled domain
B . To improve the IGP convergence time
C . To hide visibility to the core (provider) routers in the MPLS network
D . To provide a visible extension of IP TTL functionality in an MPLS-enabled domai