An optically active alkyne A (C10H14) can be catalytically hydrogenated to butylcyclohexane. Treatment of A with C2H5MgBr liberates no gas. Catalytic hydrogenation of A over Pd/C in the presence of quinoline poison and treatment of the product B with O3 and then H2O2 gives an optically active tricarboxylic acid C8H12O6. (A tricarboxylic acid is a compound with three –CO2H groups.) Give the structure of A (without stereochemistry).