In "April 2000: The Third Expedition," why is Captain John Black reluctant to leave the spaceship when he and his crew members first land on Mars? A. He begins to realize he isn't as brave as he thought he was. B. He doesn't like what he sees outside the port window. C. He fears there isn't enough oxygen in the Martian air to support human life. D. He thinks his crew members don't have enough weapons to protect themselves.