Hello STudent,

First of all you should determine whether you go for Union Public Service commission civil service examination or for your masters. Because you cannot prepare for or two of this together. UPSC CSE or IAS exam is one of the toughest examination in India. So you should prepare well for this if you have a clear view target. You have to practice again and again.

As you are coming from Science background, both sociology and history is new for you. If you choose history it will be a safe option. Because you just have to go through NCERT fundamental books thoroughly to score the highest marks in history.

Go to the link below to have a better idea

https://competition.careers360.com/articles/how-prepare-for-upsc-ias