What is the conjugate base of phenol, ${{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{\text{OH}}$?

A.     ${{\text{C}}_6}{\text{H}}_4^ -$–OH

B.     ${{\text{C}}_6}{{\text{H}}_5}$–$\mathop {\text{O}}\limits^ +  {{\text{H}}_2}$

C.     ${{\text{C}}_6}{{\text{H}}_5}$–${{\text{O}}^ - }$

D.     ${{\text{C}}_6}{\text{H}}_6^ +$–OH

C