A

Teeth with advanced attachment/bone loss (>50%), class II–III furcation involvement, and marked mobility are classified as “questionable” because their long-term retention is uncertain but not yet hopeless; this matches the description given, whereas “poor” is usually limited to ≤50 % loss with class II furcations, and “hopeless” implies ≥75 % loss or non-restorable defects [McLeod 1998 PMID 9922760; Graetz 2011 PMID 21627675].