Which of the following requires more planning and preparation in its implementation?

Just-In-Time (JIT) inventory management requires a significant amount of planning and preparation due to its focus on reducing inventory levels and producing goods only as they are needed. The essence of JIT is to minimize waste and optimize efficiency by synchronizing production schedules directly with demand. This necessitates meticulous coordination with suppliers and production processes to ensure that materials arrive precisely when they are needed, thus avoiding stockpiling.

The implementation of JIT also necessitates careful forecasting and demand analysis, requiring a deep understanding of market trends and customer needs. Companies must develop strong relationships with suppliers to ensure reliability and timely delivery, which adds further complexity to the planning stage.

In contrast, other options like mass production and batch production typically involve established procedures and systems that do not require as much real-time adjustment to align with demand fluctuations. Lean manufacturing, while also focused on reducing waste, often incorporates elements of both JIT and batch production and may not demand the same level of intensive supply chain coordination as JIT alone.