Hey,
BBA or Bachelor of Business Administration is a three year long undergraduate programme that equips you with leadership and Management skills required to excel in the world of business. This course brings with itself huge number of opportunities only if you have the required skills. In any sector,administration experts play significant role. You can work in different government and private companies. If you do MBA then the career opportunities will increase for you.
BCA or Bachelor in computer applications is a three year undergraduate programme that teaches you to work with Computers,web applications,internet and so on. The career opportunities is quite high for BCA graduates as the IT industry is growing rapidly day by day.
See,both these fields are good but you should choose the subject that you are passionate about.
Hope this helps.
Good luck.