Which of the following statements is true regarding JIT and MRP?

The statement indicating that MRP is used for planning while JIT is used to put the plan into effect is accurate.

MRP (Materials Requirements Planning) serves as a tool for determining material requirements needed to support production schedules. It focuses on planning inventory levels and scheduling production based on forecasts and demand. MRP helps in organizing procurement and managing inventory so that materials are available when needed.

On the other hand, JIT (Just-In-Time) is a production strategy aimed at reducing waste and increasing efficiency by receiving goods only as they are needed in the production process. This approach aligns closely with demand, minimizing inventory levels and reducing holding costs. JIT emphasizes continuous improvement and a responsive production system, effectively executing the plans that have been laid out by MRP.

Therefore, the distinction that MRP is primarily concerned with the planning phase and JIT focuses on the execution phase logically supports the correctness of the chosen statement. The other options, which imply that one of the systems renders the other obsolete or that both systems can be similarly categorized, do not accurately reflect the relationship between MRP and JIT.