In this section, you will hear five short news items. After each item,which will be read only once, there will be a twenty-second pause. During the pause, read the question and the four choices marked A, B, C and D, and decide which is the best answer. Then mark the corresponding letter on the answer sheet with a single line through the centre. Why was scientific satellite MAVEN sent to space
A．To find out if there are any living creatures or plants on Mars. B．To collect water samples from Mars and learn what is happening on Mars. C．To learn what happened to the atmosphere and water on Mars. D．To study the geological and geographical conditions on Mars.