When vapour of alcohol is passed over Ag powder at 300∘C the product is isobutene. Alcohol in this reaction will be: (a) CH3−CH2−OH|CH−CH3 (b) CH3−2−OH|C|CH3−CH3 (c) CH3╲╱ CH3CH−OH|C|CH3−CH3 (d) CH3−OH|C|CH3−CH3