Which of the following alcohols is dehydrated most readily with conc. ${\mathrm{H}}_2{\mathrm{SO}}_4$?

Dehydration of alcohols by conc. ${\mathrm{H}}_2{\mathrm{SO}}_4$ takes place according to following steps:

the slowest and fastest steps in the above reaction are:

 Major product is:

Which statement is true for the above reaction? 

In the reaction

${\left({\mathrm{CH}}_3\right)}_3\mathrm{C}-\mathrm{O}-{\mathrm{CH}}_2{\mathrm{CH}}_3+\underset{ (1\mathrm{mole}) }{\mathrm{HI}}\stackrel{ \mathrm{heat} }{⟶}$

the product$\left(\mathrm{s}\right)$ formed is (are)

In the reaction

the major product formed is

In the reaction  the product $\left(\mathrm{A}\right)$ has the structure: