Concept:
Different Indian sculptural traditions used distinctive materials according to regional artistic practices.
Step 1:
Indus Valley seals were commonly made of:
\[
Steatite
\]
Thus:
\[
A \rightarrow III
\]
Step 2:
Bharhut railings were carved in:
\[
Beige Sandstone
\]
Thus:
\[
B \rightarrow IV
\]
Step 3:
This sculpture is associated with:
\[
Reddish Brown Sandstone
\]
Thus:
\[
C \rightarrow I
\]
Step 4:
South Indian Krishna sculptures of this type are often cast in:
\[
Bronze
\]
Thus:
\[
D \rightarrow II
\]
Therefore, the correct matching is:
\[
A-III,\; B-IV,\; C-I,\; D-II
\]
Hence, the correct answer is:
\[
\boxed{\text{(1) A-III, B-IV, C-I, D-II}}
\]