Context: Read the passage about the Mars robot Curiosity.
People can't make it to Mars yet. It takes too long to get there, and it's not an easy place to live. So, scientists sent a robot to look around Mars for them. The robot is named Curiosity. One of its jobs is to find out if anything can live on Mars.
Curiosity has many cameras. It takes pictures as it moves around Mars. Curiosity sends the pictures back to the scientists on Earth. Scientists hope that the pictures will make it easier for us to visit Mars someday.
What is one reason people can't go to Mars?
A. It's too far away.
B. It's too hot there.
Determine the correct option from the provided choices and reply with its corresponding letter.
Answer: A