【单选题】

{{I}}Questions 17 to 20 are based on the following passage.At the end of the passage, you will be given 20 seconds to answer the questions. Now listen to the passage{{/I}} When will people probably be able to live on Mars

A、In 200 years.
B．In 10,000 years.
C．In 100,000 years.
D．Unknown.