(a) Molecule A, C10H16, is optically inactive. A reacts with excess H2 and PdC to give a product with formula C10H2a. When A reacts with excess ozone at -78 °C

followed by Z nand aqueous acid, the only product is B, formed as a racemic mixture. How many pi bonds does A have? How many rings does A have? The data are compatible with 2 structures for A. Write only one of them, including wedge/dotted bonds at chirality centers.