Which Functional Group Is a Carboxylic Acid?
A) - OH $\begin{array} { c } \mathrm { O } \\\| \\\quad- \mathrm { C } \mathrm { OH }\end{array}$

Which functional group is a carboxylic acid?

A) - OH
B) $\begin{array} { c } \mathrm { O } \\\| \\\quad- \mathrm { C } \mathrm { OH }\end{array}$
C) $\begin{array} { c } \mathrm { O } \\\mathrm { || } \\\quad\quad- \mathrm { C } - \mathrm { O } -\end{array}$
D) $\begin{array} { c } \mathrm { OH } \\\mathrm { | } \\\quad\quad- \mathrm { C } - \mathrm { OH }\\\mathrm { | } \\\end{array}$
E) - CH?OH