Read the paragraph.
Solar flares are explosions that occur above the sun’s surface. They usually erupt around sunspots, which are places on the sun where gases are cooler than the gases around them. Solar flares are powerful. When a solar flare occurs, gas shoots out from the sun and energy escapes into space. If this energy reaches Earth, it can cause problems such as interference with radio signals or power outages. Solar flares, as viewed from Earth can also be beautiful. Auroras are colorful displays of light that can be seen in the night sky.
Question: Imagine that your teacher assigned you the following topic: What is a solar flare? You wrote this passage in response. What does the underlined sentence add to your essay?
A: It gives an historical example about solar flares.
B: It cites expert testimony about solar flares.
C: It explains why solar flares are powerful.
D: It gives readers a definition of solar flare.
