Cl—CH2—CH2—OH



When acidic H is eliminated, the stability of the anion directly relates to its acidic nature. Since the negative charge in phenol created once the acidic H is removed will be delocalized over the whole ring. That makes it the most stable. So, the most acidic chemical will be phenol.
Therefore, the correct option is (B):

Arrange the following compounds in increasing order of their boiling points:

The reaction 
suggests that phenol is :
In the reaction R–OH + HCl $\xrightarrow{\text{ZnCl}_2}$ RCl + H$_2$O, what is the correct order of reactivity of alcohols?
Read More: Alcohols, Phenols, and Ethers