Answer:
The reactant/reagent that would be most atom economical is EtI (Ethy Iodide) and KOH (potassium oxide) as base
This is because the iodo group are weak base hence they have a good leaving character (i.e they are unstable on their own ) which would increase the rate of reaction and the strong base KOH give the most atom economical
Explanation:
Lipid you can look up the chemical structures and lipids are the longest which make them the largest