Two alcohols, A and B, have the same molecular formula C₉H₁₀O and react with sulfuric acid to give the same hydrocarbon C. Compound A is optically active, and compound B is not. Catalytic hydrogenation of C gives a hydrocarbon D, C₉H₁₀, which gives two and only two products when nitrated once with HNO₃ in H₂SO₄. Give the structures of A, B, C, and D.