Which is the most profitable fields of study in business?

Accounting may be the right fit for you only if you are an above average student. Average and below average students cannot earn the good grades that accounting majors must have to get the good job offers. As for the most lucrative field, it depends on you and not the field. A marketing graduate may end up becoming a multi-millionaire, while another is getting unemployment benefits. A finance graduate may make a fortune while another works for McDonald's. An accounting graduate may be a partner earnings $400,000 a year while another is bookkeeper for a small company. Here is a true scenario:

Mike is a good student majoring in [finance], [economics], [marketing] with good grades, graduates and gets a good job with a large firm. Mike works hard, advances, and in four years gets promoted to executive management level X.

Joe is a good student majoring in accounting and earns good grades, graduates and gets a good job with a large CPA firm. Joe works hard auditing the firm's clients and after two years on the job gets an offer from one of the clients to take a job at executive management level X. That is what accounting experience does; you advance at twice the rate of other business majors. Alternatively, Joe may decline the job offer and remain in accounting reaching partnership level in 8-10 years.

Marketing clearly

Out of what you mentioned--Economics

But MIS if you consider information system management