Which subject to choose totally depends on your interest. You should just move with your consistency, adopt your strategy and firmly follow it. Pls stick to the optional you have selected and put your best efforts into it, never keep moving with them. And if by chance you do not performed well in thr first attempt don’t think of changing it rather this time give your utmost plus recall the mistakes you committed, so that you don’t repeat it but use them as a tool for your success.And you should never go by the advertisements which claim to give success guarantee. Just be determined and you will surely achieve success!!