Choose a small or medium sized existing business as a client. This is considered as one with less than 200 employees.

Follow exactly what the brief says. At the end of the brief, there is a table to follow, use the last column

Also, is for a Australian University. And the assessment requires to choose a small Australian business, following these requirements: (this is very important)

Choose a small or medium sized existing business as a client. This is considered as one with less than 200 employees. Students may also like to consider a small business in their local area /neighbourhood to focus on or even a business run by friends or family. This business must be business to consumer (B2C), based in Australia, and currently operating.
Tips for choosing your business:
Keep your business choice simple. The idea of this subject is to apply, analyse and formulate ideas based on marketing theories and concepts. If you dont understand your chosen business or if its overly complicated, you will find it difficult to work within the defined parameters.
Choose something you are familiar with and somewhat interested in.
Avoid large companies and chain stores. Apple, Coca-Cola, McDonalds, Telstra, Holden for example, are too large and complex to work with.