Sarah: I just watched a documentary about exoplanets. It's amazing to think there are planets orbiting stars other than our Sun!
David: Yeah, it really makes you wonder how many of them might have conditions suitable for life.
Sarah: And the technology they use to find them is so advanced. They look for tiny dips in a star's brightness or the slight wobble of a star caused by a planet's gravity.
David: It's a whole new frontier in astronomy, trying to understand how common planets are in the universe.
What is the central theme of this short dialogue?
A) The search for extraterrestrial life
B) The methods of observing stars
C) The existence and detection of exoplanets
D) The challenges of space travel