Concept:
Plant groups are identified by their structure, reproduction and evolutionary level.
Step 1: Match Algae.
Volvox is a green alga.
\[
A\rightarrow I
\]
Step 2: Match Gymnosperm.
Pinus is a gymnosperm.
\[
B\rightarrow II
\]
Step 3: Match Pteridophyte.
Selaginella is a pteridophyte.
\[
C\rightarrow IV
\]
Step 4: Match Moss.
Sphagnum is a moss.
\[
D\rightarrow III
\]
Therefore, the correct matching is:
\[
A-I,\ B-II,\ C-IV,\ D-III
\]
\[
\therefore \text{Correct Answer is (C)}
\]