Answer
While the light reactions are not powered by the Calvin cycle, they do depend on the Calvin cycle in two ways: 1) They need to have NADPH and ATP returned to $NADP^{+}$ and ADP so that the light reactions can continue, and 2) They need the products of photosynthesis since those are used to synthesize all other kinds of things in cells, including the enzymes which conduct the light reactions.
Work Step by Step
This question wants you to use your imagination to think backwards, to see what about the Calvin cycle is required for the light reactions. Think about what the Calvin cycles produces (including used up energy carriers) and how these products relate to the light reactions.
