Answer: A

Reasoning: The periodontal ligament (PDL) adapts to functional demand—reduced masticatory load narrows the PDL space, whereas greater but still physiologic load causes compensatory widening; only when loads exceed physiologic limits does trauma occur. Animal studies show that softer diet (lower load) “narrowed periodontal ligament space,” implying the converse (higher physiologic load) widens it [Niver et al., 2011, PMID 21848615]. Hence, excessive forces within the physiologic range increase PDL width.