I am writing a report for an assignment in which I have used Tikz/LaTex to make several plots, block diagrams and figures in general. Due to the hard work that has gone in to making them I do not want anyone else to just steal them willy-nilly. Which is why I placed a Copyright mark on the images in such a way that it doesn't obscure the main contents but it is impossible to take it without the copyright mark. Now this copyright itself is meaningless since I don't have a copyright license.
The report is for a course assignment and this issue is not too big of a deal for me but if it is reasonable then I would like to keep the copyright symbol in. However, the issue is I am not sure if such a thing is reasonable or not especially without a copyright license. What should I do?