Explanation:
\(\mathop {{{\text{H}}_{\text{3}}}{\text{C - CH = CH - C}}{{\text{H}}_{\text{2}}}{\text{ - OH}}}\limits_{{\text{Crotonyl}}{\mkern 1mu} {\mkern 1mu} {\text{alcohol}}} \to \)
\(\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\text{Allylic}}{\mkern 1mu} {\mkern 1mu} {\text{alcohol}}\)