Question 2: Which of the following statements about microgrid system is true? (single-choice,10 points) (a) Photovoltaic units generate DC power instead of AC power. (b) In a microgrid system, as

it is more flexible than the traditional power grid, the voltage on each microgrid bus could be within the range of ±30-40% of the rated value. (c) Microgrids are electricity transmission systems containing loads and distributed energy resources. (d) The unit of energy in a microgrid system could be Joule or kW.