Final answer:
A primary market transaction is d. a company undertaking an issue of securities to the public, which involves issuing securities like stocks or bonds directly to investors, often through an IPO.
Step-by-step explanation:
The question concerns the identification of a primary market transaction. A primary market transaction occurs when securities are issued for the first time and sold to investors. In the given options, the answer choice that represents a primary market transaction is: d. a company undertaking an issue of securities to the public. This process involves a company selling stocks or bonds directly to the public, often through an initial public offering (IPO), before they are available for trading on the secondary market, such as the Australian Securities Exchange (ASX). Other options like institutional investors trading shares, directors selling shares on the ASX, and securities bought and sold after the original sale, pertain to the secondary market where existing securities are traded among investors.