When implementing LDP, what is liberal label retention mode?

[answerhappygod]

When implementing LDP, what is liberal label retention mode?

A. To reduce the convergence time, the LSR willretain all the received labels in its LIB even if all the neighbor LSRs go down temporary
B. The LSR can assign it's own label for each destination network even though it has not been assigned a next hop label from the neighbor LSR
C. The LSR will store the label received from the downstream LSRs in its LIB even if the downstream LSRs are not the next hop for the destination
D. The LSR will not perform PHP if it is operating in liberal label retention mode