The reason why is because, you have to look at her intentions and the time frame she wants to wait for food at these restaurants. Beachside Sqaure has less times they have made her wait for her food more than 10 minutes, so that would be their advantage.
The final answer is 1/ (1000x^3), and I don't think there is a correct option to choose from. ( option c would be correct if it were written with round brackets)