Which one of the following esters cannot undergo claisen self- condensation ?

Question

$\begin{array}{1 1} C_6H_5CH_2COOHC_2H_5 \\ C_6H_5COOC_2H_5 \\ CH_3CH_2CH_2CH_2Cax_2H_5\\ C_6H_{11}CH_2COOC_2H_5 \end{array} $