when must the down bit be set?

According to RFC 4577, OSPF for BGP/MPLS IP VPNs, when must the down bit be set?

A.
when an OSPF route is distributed from the PE to the CE, for Type 3 LSAs

B.
when an OSPF route is distributed from the PE to the CE, for Type 5 LSAs

C.
when an OSPF route is distributed from the PE to the CE, for Type 3 and Type 5 LSAs

D.
when an OSPF route is distributed from the PE to the CE, for all types of LSAs