1. No.
2. You can actually do both.
3. The basic idea is if you leave the United States for less than six months at one go usually you are okay, you are not questioned too closely, but more than six months they question you very closely because of certain technical reasons.
At one year outside you lose your green card automatically unless you have something like a re-entry permit. If on the other hand, you are a U.S citizen there is no requirement that you have to stay in the United States. You can stay anywhere in the world, never have to come back again and you would still be a U.S citizen.
Note: Where transcribed from audio/video, this is a verbatim transcript of the referenced audio/video media delivered as oral communication, and, therefore, may not conform to written grammatical or syntactical form.
All Readers, I quote from my latest msg. to Mr. Rajiv Khanna's office. Please make yourself more aware on your issues by visiting his web-site (and positively contributing to it) and get advice from his office for your particular needs. All cases are NOT the same. Quote Dear Mr Khanna I barely get time to go to your web-site, though I know it is an ocean of information for all those awaiting their immigration process at some stage or the other. Today I happened to spend an hour there and learnt that your Office had done me good!! I live in an area which lacks Indian neighbors and in my Office too, I am the only Indian working in my whole division! Therefore, there is seldom any interaction with people who are at a similar stage as me in the Immigration process. When my I-140 was filed, your Legal Assistant Nimia Aranibar informed me of the CP option. Though I might have surprised her with my lack of knowledge on this process, she explained the process to me and answered my doubts. And she did as I opted for. No suggestions or implications or other discussion. She was very professional in giving me the information and in answering my questions on the issue. She even understood my concerns with the CP process and offered to clarify my doubts and suggested the recourse to this choice if I needed a recourse at a later date. After reading the chat-site on your web-site, I now realise that the lady was giving me good information at the right time. There are so many people on the web who feel have been un-informed of this process. I, on the contrary, have got the right information from your office and am very happy about this. Thank you and best regards Prateek Rishi Nimia, reading in copy, thank you very much for the time taken to explain me the two processes.