What are the statutory authorities that permit contracting without full and open competition?

The correct answer encompasses the statutory authorities that provide specific circumstances under which contracting can occur without the typical requirement for full and open competition. The three key scenarios identified are "unusual and compelling urgency," which allows for expedited procurement in emergencies where waiting for a standard competitive process would harm the government's interests; "national security," which pertains to procurements essential for the defense and security of the nation; and "public interest," which covers situations where, due to special considerations, it is deemed beneficial for the public to circumvent the usual competitive bidding processes.

Understanding these statutory authorities is critical for ensuring compliance with regulatory frameworks governing procurement, as they offer flexibility in cases where competition might not be feasible or practical. The other options do not comprehensively address the breadth of situations where contracting without full competition is authorized. For instance, limiting it to emergency procurements alone does not cover the other valid justifications as outlined in the correct choice. Similarly, specifying single-source availability or all sources without exception fails to recognize the nuanced scenarios that allow for non-competitive contracting, which are clearly defined in federal acquisition regulations.