The chirality is not lost on heating is case of

(b) \begin{matrix} CH_3 & – & CH & – & CH_2 & – & COOH \\ & & | & & & & \\ & & OH & & & & \end{matrix} 

(c) \begin{matrix} CH_3 & – & CH &- & COOH \\ & & | & & & & \\ & & CH_2COOH & & & & \end{matrix} 

(d) \begin{matrix} & & OH & & \\ & & | & & \\ CH_3 & – & CH & – & COOH \end{matrix}