$\begin{array}{1 1} (a)\; \text{Oesophagus, Large Intestine, Rectum} \\ (b)\; \text{Buccal cavity, Oesophagus, Large Intestine} \\(c)\; \text{Buccal cavity, Oesophagus, Large Intestine}\\ (d)\; \text{Small intestine, Large intestine, Rectum} \end{array}$