In this section, you will hear one passage. At the end of the passage, you will hear four questions. Both the passage and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D).A、It is mainly made of rock and ice.
B、Its full orbit around the sun lasts almost 250 Earth years.
C、It took about 11 years for NASA to discover Pluto.
D、It used to be the smallest planet.