The track isn't a red herring, although TA's explanation is probably simpler in this case (constant track to / from the NDB).
Magnetic Bearing - Magnetic Heading = Relative Bearing
As you are flying a TRACK of 145° from the NDB, the MB to the NDB is the reciprocal of 145° = 325°
As TA has said, there's 5° right drift, so your HEADING is 140° to counteract the drift.
Therefore RB = 325° - 140° = 185°