When one equivalent of Br₂ reacts with 2,3-dimethylbuta-1,3-diene, two alkene products are formed. Determine which alkene is more stable. Why?

• A. Alkene (b) is more stable due to a lower degree of substitution around the double bond.
• B. Alkene (b) is more stable due to a higher degree of substitution around the double bond.
• C. Alkene (a) is more stable due to the trans geometry.
• D. Alkene (a) is more stable due to a higher degree of substitution around the double bond.

Answer: (D)