Which sentence best supports the assertion that the sending people to the moon is a crucial step toward sending people to Mars? A) "Although Americans first walked on its surface almost 50 years ago, our explorers left footprints at only six sites, during a total of 16 days on the surface." Eliminate B) "The Gateway also will be assessed as a platform for the assembly of payloads and systems; a reusable command module for lunar vicinity and surface exploration." C) "The lunar surface will serve as a crucial training ground and technology demonstration test site where we will prepare for future human missions to Mars and other destinations." D) "A key component of establishing the first permanent American presence and infrastructure on and around the Moon is the Gateway, a lunar orbiting platform to host astronauts farther from Earth than ever before." (In High School)