Because of the costs involved in maintaining high temperatures and pressure, is not yet a practical method for generating electrical energy.

The answer is Fusion

The correct answer is "fusion".

Nuclear fusion requires very high temperatures and pressure. Nuclear fusion occurs naturally in the Sun's core. In the fusion reaction two hydrogen atoms combine to form helium atom. Very high temperatures and pressure is required to overcome the high forces of repulsion between two positively charged protons. The two protons must come together to form helium.

on passing the small ampere of electric current through the tube made of ar and hg of cfl generates uv rays which excites the fluorescent and thus emits the high radiation by consumption of just 5- 12 w in comparison to incandescent light which requires more power such as around 40 - 55 w to lighten.

moreover the life span of fluorescent or cfl is around 8000 h whereas the life span of incandescent is around 1200 h

hence, the building installed with incandescent lights bears more electricity bill.

c. 4.54 x 10–12 j happens to be correct