The author references Einstein's theory of general relativity for which of the following reasons? A. To argue that the equations of electricity and magnetism are more important than the equations of relativity B. To provide an example of an equation that has been unwavering in time C. To advocate that Maxwell was a more important historical figure than Einstein D. To show that the implications of Maxwell's equations are far more powerful than General Relativity E. To provide an example of an important equation that has been modified over time