Concept:
Sudhir Patwardhan is a contemporary Indian painter best known for his figurative works depicting urban life, workers, and the everyday experiences of common people. Among the given titles, Conversations and Nagrik are his works.
Step 1: Examine each title.
\[
\begin{aligned}
A.\ \textit{Conversations} &\rightarrow \text{Sudhir Patwardhan}\ (\checkmark)
B.\ \textit{Mumbai Proverbs} &\rightarrow \text{Not by Sudhir Patwardhan}
C.\ \textit{Killing 2} &\rightarrow \text{Not by Sudhir Patwardhan}
D.\ \textit{Nagrik} &\rightarrow \text{Sudhir Patwardhan}\ (\checkmark)
E.\ \textit{Geometric Abstraction 4} &\rightarrow \text{Not by Sudhir Patwardhan}
\end{aligned}
\]
Step 2: Identify the correct works.
The paintings by Sudhir Patwardhan are
\[
\boxed{\textit{Conversations} \text{ and } \textit{Nagrik}}
\]
Hence,
\[
\boxed{\text{(A)}}
\]