In the following sequence of reactions a compound A, (molecular formula \( \mathrm{C_6H_{12}O_2} \)) with a straight chain structure gives a \( \mathrm{C_4} \) carboxylic acid. A is:
\( \text{A} \xrightarrow[\mathrm{H_3O^+}]{\mathrm{LiAlH_4}} \text{B} \xrightarrow{\text{Oxidation}} \mathrm{C_4} \text{ - Carboxylic acid} \)
