Hey!
According to me, there are no easy or hard subjects, it's just that we need to have the right kind of mindset. If we try, we can study every subject with ease.
But definitely, some subjects are a bit tougher to understand. It depends on person to person. Some people find history easier, whereas other one might think psychology.
According to me, English is the easiest of all the subjects. Not only in arts stream, but for every stream, it is the easiest subject. It is easy to read and understand it.
But again, different people may have different choices.
Hope this answer helps!