Different theoretical AMRFs for three different primary masses: 9 M_⊙ (blue), 20 M_⊙ (orange), and 30 M_⊙ (grey). The solid black line shows the theoretical AMRF for MS+BH systems, the dotted curves are for main-sequence binaries, and dashed curves are for triple main-sequence systems. Different classes are also indicated for the 30 M_⊙ primary by the horizontal dotted lines at the maxima of the triple-AMRF and the main-sequence AMRF (Class III: identifiable OB+BH systems, Class II: triple main-sequence or OB+BH systems, Class I: OB+OB binaries, triple main-sequence systems, or OB+BH binaries).