Structure of $A$ is

Which series of reactions will achieve the following transformation?

$1, 2-$dibromocyclooctane $\xrightarrow[\substack{\text{(ii) } NaNH_2 \\ \text{(iii) } Hg^{2+} / H^{+} \\ \text{(iv) } Zn-Hg / H^{+}}]{\text{(i) } KOH \text{ (alc.) }} \underset{\text{(Major product)}}{P}$. $P$ is

The increasing order of carbon-carbon bond length for the following is:

Compound $(X)$ will be:
Compound $(X) \xrightarrow[Pt]{5H_2} \text{Saturated compound}$
Compound $(X) \xrightarrow{AgNO_3} \text{Precipitate}$
Compound $(X) \xrightarrow[Me_2S]{O_3} OHC-CH_2-CH_2-CO-CHO + HOOC-CHO + HCOOH + OHC-CHO$

The major products from the following reaction sequence are product $A$ and product $B$. The total sum of $\pi$ electrons in product $A$ and product $B$ are . . . . . . .(nearest integer)