Final answer:
The major challenge for today's supply chain managers is finding reliable low-cost suppliers, while also integrating new technologies and safeguarding labor rights to maintain a resilient and efficient supply chain.
Step-by-step explanation:
Among the options provided, finding reliable low-cost suppliers is a significant challenge for today's supply chain managers. Other challenges include integrating new technological advancements and ensuring the protection of labor rights within the supply chain. Continuous improvements in technology, transportation methods, and policies are vital to maintaining a resilient supply chain during times of national emergencies. Additionally, companies are encouraged to invest in their labor force and update their labor policies to promote a sustainable and efficient supply chain network.