Determine if the given pair of molecules are identical or isomers. If they are isomers, are they enantiomers, diastereomers, or constitutional isomers?

• A. (i) identical; (ii) constitutional isomers.
• B. (i) enantiomers; (ii) constitutional isomers.
• C. (i) constitutional isomers; (ii) diastereomers.
• D. (i) diastereomers; (ii) identical.

Answer: (C)