Padmapalasaki and Chandrakantha purchase an Indian restaurant from Priya. It is located in Glen Waverly, south-east of Melbourne. In order to ensure she does not establish a similar restaurant in the same vicinity, they include a term in the contract that prohibits Priya "owning or managing" a restaurant within a 20-km radius of the restaurant for five years. Advise them whether this term would be an illegal restraint.