TOEFL Listening: ETS-TOEFL听力机经 - 353XYMLJV9Z1WGB4P$

Why does the professor mention the Pulsar? A. To illustrate one step in the life cycle B. To give an example of a dead star around planet C. To provide a key distinction between the fate of the Sun D. To explain why planets are rarely discovered revolving around white dwarfs.