You can write about any topic in business law. If you open any book about commercial law, you will find several topics. You can write any one of them. In addition, our course contains the core of business law. So, you can write about any topic inserted in our course. I do not want to restrict you with specific topics in order to facilitate your duty. So, you can select any topic. Examples: contract of sale, contract of carriage of goods, contract of carriage of persons, contract of agency, the trader, obligations of the trader, bankruptcy of the trader, general partnership, joint-stock company, limited liability company, the holding company, the shares, the bonds, the banking transactions, etc.
It is better to use books and researches as references. But because of the current circumstances, you can use the internet sources. But do not copy and paste.
Usually, the assignment contains Introduction, body, conclusion and the references.
Do not use one reference only. They should be two or more.