You might be better off listening to your parents until you can demonstrate a hobby or ability with a future.

i would try to pass your classes later so you can do what you want to do

Let me get this clear - you are preparing to take the JEE Advanced and you want to study business?! Your parents want you to go into something more technical, I assume. I really don't know how things are in India, but, here in the USA, a lot of people with very high aptitude go on to study hard science, only to switch over to MBA in graduate school, or to business in their career. I'd assume things are a little more predetermined there, since the USA has ***freedom***. I'm sure your parents want to see you succeed, and, although they might not know what's best for you perfectly, they do have more experience with life. It's a tough call, since I don't know what your options are. When I went to the university, I wanted to study music. My parents wanted me to study physics. I signed up for music classes, and flunked a class my first semester, due to circumstances completely outside of my control (and outside of the rules of the department and the university). I appealed and fought with the department for months afterward, and in the mean time, switched majors to physics. Even though the subject matter was much more demanding than music, and I had less interest, the department had no room for bullshit (like what caused me to fail music), so I excelled. I retook my failed music class (the school's resolution to my previous problem with the teacher was to have me retake the class with a different teacher, tuition-free) and got a 100% score (4.0 out of 4), but, by then, I had grown to respect the cut and dried structure of the hard sciences, where grades were totally objective. The only time I had another headache in school was when I handed in my Ph. D. dissertation and the administrative people took issue with the formatting of it. But, whatever, I completed my education to the highest possible level (except an accepted dissertation), and got a really good job, and still pursued a career in music in the evenings and weekends.