Let's say I have a question asking me which would best suit the data set. How do I figure this out?

Basically, how do I know when to use a measure of variability (and which one to use) or when to use measure of center (and which one to use)?

Millie decided to purchase a $17,000 msrp vehicle at a 4% interest rate for 6 years. the dealership offered her a $2700 cash-back incentive, which she accepted. if she takes all these factors into consideration, what monthly payment amount can she expect? a.$223.73b.$243.25c.$274.61d.$235.51