C

Recurrent fetal loss is classically linked to antiphospholipid antibody syndrome; the most specific screening assay for the lupus anticoagulant in this setting is the dilute Russell viper venom time/antibody test, not routine coagulation tests or clot-solubility studies [Bick, 1999, PMID 10629391; Rawat, 2015, PMID 25825573].