DEF, Inc.

Given the situation at DEF, Inc., where the supply manager is concerned about the diminishing specialty supply base and the increasing demand for precious metals, the best strategy involves managing the supply chain more effectively:

Option A, risk avoidance, is a general strategy that might not address the specific issues of supply constraints and demand growth.

Option B, value stream mapping, is useful for identifying inefficiencies but does not directly solve the problem of supply base reduction and growing demand.

Option C, transformation management, involves significant changes in processes and may not be immediately feasible or effective in this context.

Option D, multi-tier purchasing agreements, involves engaging with multiple suppliers at different levels of the supply chain. This approach can help secure a more stable supply base by diversifying sources and leveraging combined volumes for better pricing and reliability. It addresses the concerns of both supply continuity and cost management effectively.

References:

Strategies for managing supply chain risk.

Benefits of multi-tier purchasing agreements in supply chain management.