It shall be unlawful for any person, in connection with the offer, sale, or purchase of any security, directly or indirectly
(a) To employ any device, scheme, or artifice to defraud;
(b) To make any untrue statement of a material fact or to omit to state a material fact necessary in order to make the statements made, in the light of the circumstances under which they are made, not misleading;
(c) To engage in any act, practice, or course of business which operates or would operate as a fraud or deceit upon any person;
(d) To fail to deliver the prospectus filed under the "Securities Act of 1933" to each purchaser of a security registered under that act, in accordance with the prospectus delivery requirements of that act.