Select the text from the paragraph that best helps you understand that microlensing means a method of...

Select the text from the paragraph that best helps you understand that microlensing means a method of observing objects based on how their gravity affects light from a background source. There may be more than one correct choice.
Most known planets in the Milky Way orbit stars, but there are certain "rogue planets" that are not bound to a star and simply orbit the gravitational center of the galaxy. Such planets can be difficult to find. Astronomers' usual methods for identifying a planet outside our own solar system rely on observing the effect of the planet on the star it orbits; since they lack a host star, many rogue planets are difficult to detect. However, astronomers can sometimes locate an otherwise undetectable planet when its gravitational field briefly magnifies incoming light from more distant stars. A rogue planet may also emit enough radiation to be detected through infrared imaging. Which of these two approaches is most appropriate depends on the characteristics of the object being observed: microlensing works best to expose more massive objects, while infrared imaging is most effective for hot ones.