Answer:
Price of the meals
Scatter plot with a trendline
Explanation:
None of the provided options are correct. The independent variable was Price of the meals, and they should present the data as a Scatter plot with a trendline. The Price of the meal is the independent variable because it does not depend on any other variable and is instead the cause of the burping frequency which would be the dependent variable in this scenario. The Scatter plot would allow you to mark each individual's burping frequency on the same prices for the meal, since you would most likely have more than one value of burping frequency for the same priced meal.