Conversation so far:
how many canidates are there?
On January 6, 2009, CNN announced that Gupta had been considered for the position of Surgeon General by President Barack Obama.
how come he didnt get it?
In March 2009 Gupta withdrew his name from consideration for the post, citing his family and his career.
how long did he work for cnn?
CANNOTANSWER.

Question: why did Obama nominate him?
Self-contained rewrite: why did Obama nominate Sanjay Gupta for Surgeon General?