Which of the following alcohols has the lowest boiling point?

Major products $(C)$ and $(D)$ will be respectively:

Most acidic alcohol out of the following compounds is

Identify the major product of the following reaction:
$(CH_3)_3C-CH(OH)-CH_3 \xrightarrow[\Delta]{\text{conc. } H_2SO_4} \text{Major product}$

What will be $A$,$B$,$C$,and $D$ in the following reaction sequence?
Cyclohexanol $\xrightarrow[H_2SO_4]{CrO_3} A$ $\xrightarrow[(ii) H_3O^+]{(i) CH_3MgI} B$ $\xrightarrow{\Delta, H_2SO_4} C$ $\xrightarrow[(ii) H_2O_2, NaOH]{(i) (BH_3)_2} D$

Identify the unknown $(A)$ in the reaction: