Which one is an unsaturated compound?

The reaction is $2\text{-methylbuta-1,3-diene} + HBr \rightarrow \text{products}$. Identify the correct statement regarding the products of this reaction.

Aqueous sulphuric acid reacts with $2-$methyl$-1-$butene to give predominantly

Identify the product of the following reaction: $CH_3-CH=CH-CH_3 \xrightarrow[(ii) H_2O, Zn]{(i) O_3} \text{Product}$

Predict the major product for the following reaction:
$CH_2=CH-CH_2-I \xrightarrow{HI \text{ (Excess)}} ?$

Suppose the following reaction,the major product will be: