A

Intrusion requires light forces—about 10-20 g per incisor; for four mandibular anterior teeth this totals roughly 40-80 g, so the closest listed value is 50 g [A]. Clinical studies using Burstone-type intrusion arches apply ≈15 g per tooth, confirming this low-force range [Costopoulos & Nanda, 1996, PMID 8638600].