Astronaut Mark Kelly announced today that he is retiring from NASA in order to focus on the recovery of his wife, Gabrielle Giffords. Kelly, who is 47, began his NASA career in 1996. He has traveled to the International Space Station four times and served aboard space shuttles    Endeavour and Discovery.  Most recently he was commander of Endeavour's final voyage, which ended on June l.  "After 25 years of service to our country, I am retiring from the United States Navy and leaving NASA. My retirement will take effect on October l. " he said. "This was no easy decision. Words cannot express my deep gratitude for the opportunities I have been given to serve our great nation. And I have always been proud to be a member of the NASA. Public service has been more than a job for me and for my family. My brother continues to serve in NASA and in the Navy. My parents are retired police officers. And my wife Gabrielle proudly serves in the US House of Representatives." he continued.  "As life takes unexpected turns we frequently come to a crossroads. I am at this point today.  Gabrielle is working hard every day on her way to recovery.  I want to be by her side.  Stepping aside from my work in the Navy and at NASA will allow me to be with her and with my two daughters. I love them all very much and there is no doubt that we will move forward together. After some time off, I will look for new opportunities and I'm hopeful that one day I will again serve our country." Kelly said. On Jan 8, Giffords was shot in the head and was severely injured while meeting with her supporters. She returned to her Tucson home last week for the first time since then. Mark Kelly decides to retire from NASA mainly because_.
he is tired and hopes for a good rest he has been offered a better position he was commander of Endeavour's final voyage he hopes to spend more time with his family
Question: Astronaut Mark Kelly announced today that he is retiring from NASA in order to focus on the recovery of his wife, Gabrielle Giffords. Kelly, who is 47, began his NASA career in 1996. He has traveled to the International Space Station four times and served aboard space shuttles    Endeavour and Discovery.  Most recently he was commander of Endeavour's final voyage, which ended on June l.  "After 25 years of service to our country, I am retiring from the United States Navy and leaving NASA. My retirement will take effect on October l. " he said. "This was no easy decision. Words cannot express my deep gratitude for the opportunities I have been given to serve our great nation. And I have always been proud to be a member of the NASA. Public service has been more than a job for me and for my family. My brother continues to serve in NASA and in the Navy. My parents are retired police officers. And my wife Gabrielle proudly serves in the US House of Representatives." he continued.  "As life takes unexpected turns we frequently come to a crossroads. I am at this point today.  Gabrielle is working hard every day on her way to recovery.  I want to be by her side.  Stepping aside from my work in the Navy and at NASA will allow me to be with her and with my two daughters. I love them all very much and there is no doubt that we will move forward together. After some time off, I will look for new opportunities and I'm hopeful that one day I will again serve our country." Kelly said. On Jan 8, Giffords was shot in the head and was severely injured while meeting with her supporters. She returned to her Tucson home last week for the first time since then. Mark Kelly decides to retire from NASA mainly because_.
A. he is tired and hopes for a good rest
B. he has been offered a better position
C. he was commander of Endeavour's final voyage
D. he hopes to spend more time with his family
Answer: