Consider the following reaction

  

   What is/are true regarding the above reaction?

Decarboxylation is facilitated by the presence of any carbonyl group at the $\beta -$Position, including that of carboxyl group (or) ester.  The mechanism followed through a cyclic, six members.  Transition state involving rearrangement of $3e^{\Theta }$ pairs gives the enol form of a carboxylic acid, which is tautomerized to the carboxylic acid.