The sentence uses the form gets along famously on, which is incorrect and needs improvement. Using the preposition ‘on’ is incorrect here, hence it has to be corrected. The correct phrasal verb to be used here is gets along famously with. To get along with is a phrase which means to be on good terms with. e.g. Don't worry Aisha, I get along with your mom really well. The only alternative that improves the sentence is A. None of the other alternatives can make the sentence meaningful. Therefore, the correct answer is option 1.