Final answer:
The IEEE assigns a manufacturer's Organizationally Unique Identifier (OUI), which is a part of the MAC address used for identifying hardware on a network. The correct option is a.
Step-by-step explanation:
The institution responsible for assigning a manufacturer's Organizationally Unique Identifier (OUI) is a) IEEE (Institute of Electrical and Electronics Engineers). The IEEE is an organization that develops and manages standards for electrical, electronic, and related technologies. An OUI is a 24-bit number that uniquely identifies a vendor, manufacturer, or other organization globally.
The other acronyms represent different organizations: b) ISO stands for the International Organization for Standardization, c) FCC is the Federal Communications Commission, and d) ICANN is the Internet Corporation for Assigned Names and Numbers. However, it is the IEEE Registration Authority that assigns OUIs as part of the MAC address used for networking hardware.
Hence, Option a is correct.