Mulk Raj Anand's Untouchable was published first among the given works.
The Sword and the Sickle came after it.
Seven Summers was published later.
The Old Woman and the Cow came after these works.
Therefore, the chronological order is:
\[
\textit{Untouchable} \rightarrow \textit{The Sword and the Sickle} \rightarrow \textit{Seven Summers} \rightarrow \textit{The Old Woman and the Cow}.
\]
So the correct sequence is:
\[
C,\ B,\ D,\ A.
\]