I would pick The New York Times to investigate as it is a top-notch newspaper and also the one I read most. The Media Bias Website says that The New York Times is one of the top reliable sources for news consumption, which is ovbvious, and leans a little bit to the left (I am not sure about this). I mean I am not so surprised to know that as, honestly, I do not know much about politics and I was not so aware of whether the left and right partisans matter or not when reading newspapers. And this is just a small incline to the left so I did not feel clear about the difference. This enlightenment is kind of interesting and by knowing this in the future I will pay more attention to any source I consume.