Indicate which of the following are cross-section data. 1. Food bill of a family for each month of 2015. 2. Gross sales of 200 ice cream parlors in July 2015. 3. Number of cars sold each year by General Motors from 1980 to 2015. 4. Salaries of 50 employees. 5. Number of supermarkets in each of 40 cities as of December 31, 2015.