TOEFL Listening: ETS-TOEFL听力机经 - 14C6S8X8N7483T1FP$

Why does the professor mention seeing a flashlight shining next to a spotlight? A. To clarify how most telescopes function. B. To point out that some exoplanets can appear brighter than their parent stars. C. To help explain what diffraction patterns look like. D. To illustrate the difficulty of detecting exoplanets that orbit close to stars.