Choice "C" is correct. Among other things to prove a cause of action under Rule 10b-5, a plaintiff must prove that the defendant, in connection with the purchase or sale of securities, either made a false statement of a material fact or omitted a material fact.
Choice "b" is incorrect. Negligence is not a high enough standard; Rule 10b-5 requires scienter (either an intent to deceive or reckless disregard for the truth).
Choice "a" is incorrect. Section 10(b) and Rule 10b-5 apply to all sales of securities involving interstate commerce, not just those registered.
Choice "d" is incorrect. Section 10(b) of the 1934 Act primarily governs post-issuance transactions; issuance of securities generally is governed by the 1933 Act. Although Section 10(b) and Rule 10b-5 could be applied to the issuance of securities, this section and the rule do not require that the securities involved be part of an original issuance.