Inserting lists that correlate to different figures to fit into

Hello,

I am making a relatively simple formula, however, I cannot remember how to add a list. So for example, I have:

fuel consumption per hour 10 gallons
number of hours cruising 204
total number of gallons used 2040 gallons
type of fuel used: xyz

I want to add a list where I have written xyz with the following figures:

one gallon of fuel lbs of co2 per gallon
marine diesel 21.24
marine unleaded 93 19.88
marine unleaded 91 19.51
marine unleaded 89 19.52
Jet A 21.1
Biodiesel 5.02

And when you select for example marine diesel the number is 21.24 and that will multiply by 2040 and if you choose Jet A it will choose 21.10 and multiply 2040 by 21.1?

Would you please be able to assist on this?

Thank you very much,
Dan