I'm planning the following trip on a business class RTW:

MAN-MUC-HKG-ICN (LH/LH/TG)
ICN-YVR-DEN-ATL (AC)
ATL-IAD (UA)
IAD-MAN (BD)

This is between June 8th & 18th.

I am already BD Gold, and the BD "555" promotion is rubbish, so I'm looking to join a different program to claim my true 55,555 miles. So which one? Am I right in thinking UA won't accept D-class flights?

Will this itinerary alone get me to top-tier in any program? (I think it's about 19,000 earth miles).

What dates does the promotion run from & to?

Thanks in advance.