Final answer:
In legal matters, the waiver of a spouse's written concurrence when they cannot be located would typically be authorized by a court or appropriate entity within the judicial system. The question seems to mix family law procedures with executive officers' duties, but executive powers could parallel the situation in procedural analogy.
Step-by-step explanation:
The specific authorization to waive the requirement for a spouse's written concurrence in circumstances where their whereabouts cannot be determined would typically fall under the purview of the laws governing spousal rights and legal procedures. In legal processes, such exceptions may be granted by a court or an authorized entity within the judicial system. The quoted text, “...he may require the Opinion, in writing, of the principal Officer in each of the executive Departments, upon any Subject relating to the Duties of their respective Offices...”, relates to the duties of executive officers, which is a separate matter from family law issues. However, the ability to seek opinions could be analogous to the process in which an officer or judge might make a determination on waiving requirements due to exceptional circumstances.