Every sentence needs a verb in order for it to be considered a sentence. There are other phrases that also need a verb to be considered that type of phrase. It is important for the verb to match in number to the subject.
Therefore, the first thing you must do is determine what the subject is. Once you recognize the subject, you should figure out if the subject is plural or singular. For example, if the subject is plural, then the verb needs to be plural. In this sentence, the subject is “one.”
It is not dogs because the subject can’t be in a prepositional phrase in almost all cases. There is one instance where you look at the prepositional phrase for the subjects. However, this is not the case. One is singular, so a singular verb is needed like the word “is.”