sally is a new driver who is trying to budget for gas prices. Although he is really tight on money, he has heard that higher octane fue translates into higher gas mileage. So, he decides to conduct his own experiment to determine which fuel he should purchase. Given that he currently only drives between home, school, and his new job, sally can get by on one tank of gas per week in his toyota camry. With this in mind, he plans to purchase fuel from his neighborhood QT each Friday for three weeks. He would begin with t lowest octane (87), then the mid-grade (89), and finally the highest octane level (91) in the third week. He will track his gas mileage with each fill-up and compare his mileage to determine which octane level provides the greatest value. Sally has designed a very nice experiment, but we can't control everything in the real world. So, please answer the following question

A. Name the independent variable

B. Name the primary dependent variable.

C. Identify at least one extraneous variable that could affect the dependent variable that Hayden didn't consider

D. Explain how that factor could/would affect the dependent variable.