a subatomic particle of about the same mass as a proton but without an electric charge, present in all atomic nuclei except those of ordinary hydrogen.
The answer is; D
Solar cells usually convert solar energy into electricity which could later be reserved. The efficiency of solar cells is still low, compared to other sources, with a conversion rate of 15% - 22%. This reduces the attractiveness of solar cells as a competitive source of energy. This also makes this form of energy expensive due to its inefficiency.