Final answer:
The sentence with the correct subject-verb agreement is "The dogs bark loudly at night," where the plural subject agrees with the plural verb.
Step-by-step explanation:
The sentence that demonstrates correct subject-verb agreement is "The dogs bark loudly at night." In this sentence, the plural subject "dogs" agrees with the plural verb "bark." Proper subject-verb agreement is essential to ensure that a sentence is grammatically correct. When the subject is singular, like "dog," for instance, the verb should also be singular (e.g., "The dog barks loudly at night.")