Which of these describes a reason why nuclear power is important apex?

Nuclear energy is the most important energetic source against the shortage of fossil fuels as oil and methane. Nuclear power are a significant contribution to total electricity production; about 20% in the United states.  It involves the use of nuclear reactions that release nuclear energy to generate heat, which most frequently is then used in steam turbines to produce electricity within a nuclear power plant. 

The answer would be a.