The correct answer is C.
OBJ-1.5: Anti-counterfeit training is part of the NIST 800-53r4 control set (SA-19(1)) and should be a mandatory part of your supply chain management training within your organization. All other options may produce security gains in the network. They are unlikely to reliably detect a counterfeit item or prevent its introduction into the organization’s supply chain. Training on detection methodologies (i.e., simple visual inspections) and training for acquisition personnel will better prevent recurrences.