D

Nickel-titanium (NiTi) wires have the lowest modulus of elasticity and exhibit super-elastic “shape-memory” behavior, giving them the greatest springback and range compared with β-titanium, α-titanium, or cobalt-chrome alloys [Kusy & Greenberg, 1982, PMID 6961792; Goldberg et al., 1983, PMID 6575030]. Therefore, NiTi is the most elastic of the listed materials.