An unknown compound is placed in Br₂/CCl­₄ solution, and the brownish-red color of the solution disappears. It also undergoes catalytic hydrogenation to form dodecahydroheptalene. The compound forms cis- cycloheptane-1,2-dicarboxylic acid and malonic acid when treated with warm, concentrated potassium permanganate. Determine the structure of the unknown compound.

• A.
• B.
• C.
• D.

Answer: (C)