Final answer:
In JIT purchasing, quality control and adherence to delivery schedules by the supplier are more crucial because of immediate visibility of defects and minimal inventory, respectively. Long-term supplier contracts are also common to ensure consistency and reliability. The correct option that includes all these statements is I, II, and III.
Step-by-step explanation:
The question posed is related to the concept of Just-In-Time (JIT) purchasing and how it differs from conventional purchasing systems. In the context of JIT purchasing:
Quality control by the supplier is more crucial, as defective parts become evident immediately, making it essential to maintain high quality to avoid disruptions in the production process.
Adherence to delivery schedules by vendors is more crucial because any delay can halt the entire production line, since JIT systems operate with minimal inventory.
Long-term supplier contracts are common, as consistent standards and reliable delivery times are important to the success of JIT systems.
Therefore, the correct option in the final answer that encompasses all the aspects of JIT purchasing is: I, II, and III.