Indicated mandibular major connector for a long span edentulous ridge:: (A) Lingual plate, (B) Lingual bar, (C) Double lingual bar, (D) Labial bar
Answer is A. When posterior teeth have been lost and there is a need for additional indirect retention, the use of a lingual plate may be advantageous.
Stewart’s Clinical Removable Prosthodontics. Edition 4. Page 33