Which of the following would be the best definition of a Credit Default Swap?

		A financial derivative or contract that allows an investor to "swap" or offset credit risk with another party, typically an insurer, thereby providing price protection on a security.
		The ability to swap out of bad investment by "putting" that security back to the issuer at par
		A financial commitment whereby a government sponsored entity guarantees the security price.
		A special provision in a mortgage backed security that allows investors to swap tranches if there is a credit default incident.