Formation of diethyl ether from ethanol is based on a

Which is the best method to prepare cycloalkene from cyclohexanol?

The reaction sequence is as follows:
$2\text{-methylcyclohexanol}$ $\xrightarrow{H^+, \Delta} (A)$ $\xrightarrow{\text{cold dil. } KMnO_4} (B)$ $\xrightarrow{CrO_3} (C)$
Identify the product $(C)$.

Which is the best reagent to convert isopropyl alcohol to isopropyl bromide?
$CH_3-CH(OH)-CH_3 \xrightarrow{?} CH_3-CH(Br)-CH_3$

Which of the following alcohols shows the fastest reaction with $HI$?

Dehydrogenation of $CH_3-CH(OH)-CH_3$ gives