Damascenone has one stereogenic double bond

Steps:

• Inspect structure for chiral centers: none, as all carbons have incorrect substitution for chirality.
• Locate double bonds: one trisubstituted alkene in the side chain allows E/Z configuration.
• Count stereogenic units: single unit yields 2 geometric isomers.
• Total stereoisomers including damascenone: 2.

Why B is correct:

• One stereogenic double bond produces 2 geometric isomers, as defined by alkene stereoisomerism where restricted rotation creates distinct configurations.

Why the others are wrong:

• A: Overlooks the E/Z isomerism of the double bond.
• C: Assumes two stereogenic units, but only one exists.
• D: Implies three units, exceeding the molecule's single double bond.

Final answer: B