The factors that he should consider in his decision are D. all of the above.
He should definitely think about his budget, about whether he is able to afford buying an apartment in the city. He also needs to think about how long he plans to live there - if he is staying just for a short period of time, then it would be better to rent the apartment, instead of buying it. And finally, financial stability is another thing he needs to consider given that he may lose a lot of money if there is instability.