Propanol (c3h8o), an alcohol, and methoxyethane (c3h8o), an ether, are what types of isomers? a. functional group isomerism b. none of these c. chain isomers d. optical isomerism

Answer is: A. Functional group isomerism.

Isomers are molecules that have the same molecular formula (in this example C₃H₈O), but have a different arrangement of the atoms in space. 
Functional group isomerism is when the isomers contain different functional groups, so hey belong to different families of compounds (in this example alcohol and ether).