The difference between the timekeeping of various clocks is that they beat their gongs round the clock at different time intervals and with different frequencies. The poet uses a metaphor implicit comparison, which means comparing indirectly. The frequency at which the gong beats round the clock shows different conditions of different cities.
A compound (A) with molecular formula $C_4H_9I$ which is a primary alkyl halide, reacts with alcoholic KOH to give compound (B). Compound (B) reacts with HI to give (C) which is an isomer of (A). When (A) reacts with Na metal in the presence of dry ether, it gives a compound (D), C8H18, which is different from the compound formed when n-butyl iodide reacts with sodium. Write the structures of A, (B), (C) and (D) when (A) reacts with alcoholic KOH.