Final answer:
The correct verb to use for subject-verb agreement in the sentence is 'is', as the subject 'location' is singular.
Step-by-step explanation:
The correct answer to the question is 'is', therefore the completed sentence should read: 'The location of the reports is likely related to the passing low-pressure area.'
This question involves subject-verb agreement. The subject 'location' is singular, so the singular verb 'is' should be used. Although 'reports' is a plural noun, it is not the subject of the sentence; it is part of the prepositional phrase 'of the reports' which describes 'location'.