What do you expect to pay for gas in 2019?
I would say none of the given answers!
Firstly, it's not very linear.
Secondly, if we do assume a best-fit linear equation the result is dollars = 1.033*(years after 1998) + 25.29
Thirdly, even if we assume a particular functional form over the given years, extrapolating for a further 11 years is way too far!!