Step 1: Recall the products of the light reaction.
The light-dependent reactions of photosynthesis produce
\[
\begin{aligned}
&\text{ATP},
&\text{NADPH},
&\text{Oxygen}.
\end{aligned}
\]
Step 2: Identify the products used in the Calvin cycle.
The Calvin cycle requires
\[
\boxed{\text{ATP}}
\]
as the energy source and
\[
\boxed{\text{NADPH}}
\]
as the reducing power to convert carbon dioxide into carbohydrates.
Therefore,
\[
\boxed{\text{ATP and NADPH}}
\]
are utilized during the Calvin cycle.
Hence,
\[
\boxed{(C)}
\]
is the correct answer.