Complete the given sentence using the most appropriate verb form as per the situation:George says he’s 80 years old but nobody _____ him. (believe)

The correct answer is: B. believes

The sentence is in the present tense, so the verb “believe” should also be in the present tense. The other options are not grammatically correct in this context.

• Believed is the past tense of “believe.” It would be used if the sentence were about something that happened in the past, such as “George believed he was 80 years old, but nobody believed him.”
• Has believed is the present perfect tense of “believe.” It would be used if the sentence were about something that has happened repeatedly or for a long time, such as “George has believed he is 80 years old for many years, but nobody has ever believed him.”
• Is believing is the present progressive tense of “believe.” It would be used if the sentence were about something that is happening right now, such as “George is believing he is 80 years old, but nobody believes him.”

In this case, the sentence is about something that George says is true, but that nobody else believes. The most appropriate verb form to use is the present tense, because George is still saying that he is 80 years old, and nobody else still believes him.