For each of the following enthymematic arguments:
a. Formulate the plausible premise or conclusion, if any, that is missing but understood.
b. Write the argument in standard form, including the missing premise or conclusion needed to make the completed argument valid—if possible—using parameters if necessary.
c. Name the order of the enthymeme.
d. If the argument is not valid even with the understood premise included, name the fallacy that it commits.

No internal combustion engines are free from pollution; but no internal combustion engine is completely efficient. You may draw your own conclusion.