You can be a entrepreneur by studying any of the branches of Engineering. There are no so called preferred field of engineering. The thing which you need to become a Entrepreneur is an idea which have potential. If you can do that, then even after doing BA program you can be an Entrepreneur. So you should not think Entrepreneurs needs degree, what they think is a vision and some skills of management and articulation.

Now if you wish you can go for the coding based fields such as IT, CSE, AI & ML etc which will help you to build a application or software related to your business. This are feeble things which you can learn any way. Now if you wish to have some insightful degree for your business then going for courses such as MBA Start Up and Entrepreneurship Business Innovation / MBA Entrepreneurship Management / MBA Entrepreneurship / PGDM Innovation Entrepreneurship and Venture Development / PGP Entrepreneurship Management can be really good choice, which you can do after any degree.

For more information regarding Entrepreneurship consider the link below:

https://www.careers360.com/courses/entrepreneurship-course

I hope this helps. Wish you a great day!