Choice "D" is the correct choice. Officers, directors, and more than 10% stockholders are required to register and report under Section 16(a) of the 1934 Act. Holders of debt securities are not considered insiders and are not subject to the registration and reporting requirements.
Choice "b" is an incorrect choice. An attorney can be an insider, at least for purposes of Rule 10b-5.
Choices "c" and "a" are incorrect choices. Officers, directors, and 10% equity holders are required to register and report under Section 16(a) of the 1934 Act.