Which sentence is written correctly?

The sentence "The dog barked loudly last night" is written correctly because it uses the past tense verb "barked" to indicate that the action of barking occurred at a specific time in the past, which is specified as "last night." Additionally, the adverb "loudly" properly modifies the verb "barked," providing information about how the dog was barking.

In contrast, the other sentences either use the wrong verb tense or incorrect forms of the adverb. The use of the present tense in the other options does not align with the time frame established by "last night," leading to a grammatical mismatch in those sentences. Thus, option C effectively communicates the intended action in a grammatically correct manner.