Choice "A" is correct. Regulation A provides an exception from the full registration requirements. It provides a more simplified form of registration.
Choice "c" is incorrect. Not all intrastate offerings are exempt from registration. Only intrastate offerings made by issuer's doing 80% or more of their business in that state are exempt from registration.
Choice "d" is incorrect. Resales must qualify for their own exemption. The fact that the securities were purchased pursuant to a Regulation D offering does not mean that a resale would necessarily be exempt from the registration requirements.
Choice "b" is incorrect. Stockbroker transactions are exempt only if the transaction (i) is on a customer's order, (ii) is through an exchange or over-the-counter market, and (iii) constitutes a usual brokerage function.