Which of the following conditions does FAR Part 12 not apply for the acquisition of commercial items?

FAR Part 12 governs the acquisition of commercial items, emphasizing streamlined procedures to facilitate a more efficient procurement process. The provision allows for certain exceptions and conditions where these regulations do not apply.

In the case of purchasing through competitive negotiation, this option does not align with the intent and structure of FAR Part 12, which is designed to focus on more straightforward procurement processes typical in commercial item acquisitions. Competitive negotiation often pertains to scenarios under FAR Part 15, which involves more complex contracts that do not fit the streamlined nature of commercial item procurement.

The other scenarios, such as purchases at or below the micro-purchase threshold, using the Government-wide purchase card, and acquiring directly from another Federal agency, each fall under conditions where FAR Part 12 can still apply. These options reflect purchasing methods that either involve less complexity or involve direct transactions with other government agencies, which are consistent with the commercial item acquisition framework. Thus, C is the correct answer as it identifies a situation that requires traditional procurement processes rather than those streamlined under FAR Part 12.