"There are five volcanos." is definitely one of the correct translations and has been since my last comment 9 months ago.
However, I now taking a better look at what you posted as you answer and assuming it is the same as what you wrote in the exercise you have: ""there are are five volcanos." with "are are". It's a common mistake to write the same word twice and to overlook it when checking our answers.
Next time make a Report if you don't know why your answer was rejected. Just go to the bottom of the exercise page to Report and check "My answer should be accepted." Then make a comment here. That way we can get a clear view of your answer.