How many chain isomers are possible for $C_6H_{14}$?

The starting material is propene $(CH_3-CH=CH_2)$. The reaction with $H_3O^+$ (acid-catalyzed hydration) follows Markovnikov's rule to give $A$ (propan$-2-$ol,$CH_3-CH(OH)-CH_3$). The reaction with $(i) BH_3/THF$ followed by $(ii) H_2O_2/OH^-$ (hydroboration-oxidation) follows anti-Markovnikov's rule to give $B$ (propan$-1-$ol,$CH_3-CH_2-CH_2OH$). What is the relationship between products $A$ and $B$?

The number of isomers of $C_4H_{10}$ is:

Provide the structures and names of the chain isomers of the molecular formula $C_6H_{14}$ that contain only a methyl group as a substituent.

Identify the relationship between the structures $A$ and $B$ shown below:

Among the given structures,which can exhibit tautomerism?