Which of the Following Statements Reflects a Key Concept of a JIT

Which of the following statements reflects a key concept of a JIT production system?

A) The raw materials, work-in-process, and finished goods inventories of manufacturing companies act as buffers so that operations can proceed smoothly, even if suppliers are late with deliveries or departments are unable to operate for a brief period due to breakdowns or other reasons.
B) The use of many suppliers ensures rapid delivery of materials for production.
C) The maintenance of a stock of raw materials allows defective materials to be replaced quickly so as to maintain a high rate of productivity.
D) Inventories are costly to carry and can be kept to minimum levels or eliminated completely with careful planning.
E) Inventories of raw materials and parts, partially completed goods and finished goods are kept as a reserve against the possibility of running out.