What is the product formed when $CH_2 = CH(CH_2)_2COOH$ reacts with $HBr$?

$[CH_3-CH_2-CH(CH_3)-N^{+}(CH_3)_3]OH^{-} \xrightarrow{\text{pyrolysis}}$ major alkene will be

The reaction of $HBr$ with $CH_3-C(CH_3)=CH_2$ in the presence of peroxide will give:

An alkene $(A)$ $C_{16}H_{16}$ on ozonolysis gives only one product $(B)$ $C_8H_8O$. $(B)$ can also be obtained by the hydrolysis of the product obtained from the reaction between cyanobenzene and $CH_3MgBr$. $(A)$ shows geometrical isomerism and decolourises $Br_2$ water. $(B)$ on treatment with $SeO_2$ produces $(C)$. Which statement is not correct about $(A)$?

The major product in the following reaction is:

Which one of the following organic compounds decolourizes an alkaline $KMnO_4$ solution?