You are allowed to explore one or a combination of the elements of design and art.
As in colour, value or light/dark, line, shape, texture..etc.
So you could pick one of the above and create drawings/ paintings which are an investigative exploration of one of the above elements.
I have seen many past students body of work simply copying photographs in graphite - using hyper-realism. It would be very easy to come up with a statement to justify this.