Ozonolysis of which olefin yields $CH_3CH_2CHO$ and $CH_3CHO$?

Product $(A)$ is

For the reaction $CH_3-CH=CH_2 + HOCl \to A$,the product $A$ is:

An unknown alkene $(A)$ reacts with $3 \ mole$ of $H_2$ gas in the presence of a platinum catalyst to form $1$-isopropyl-$4$-methylcyclohexane. When the unknown alkene $(A)$ is ozonized and reduced,the following products are obtained:
$HCHO$,$OHC-CH_2-CO-CO-CH_3$,and $CH_3-CO-CH_2-CHO$
What is the structure of alkene $(A)$?

What will be the product $B$ formed in the following reaction sequence?
$CH_3CH_2CH_2OH$ $\xrightarrow{PCl_5} A$ $\xrightarrow{alc. KOH} B$

The major product of the reaction of $2-$butene with cold alkaline $KMnO_4$ is: